diff --git a/src/main/java/net/fabricmc/mappingio/FlatMappingVisitor.java b/src/main/java/net/fabricmc/mappingio/FlatMappingVisitor.java
index a495f8a0..e7eaef51 100644
--- a/src/main/java/net/fabricmc/mappingio/FlatMappingVisitor.java
+++ b/src/main/java/net/fabricmc/mappingio/FlatMappingVisitor.java
@@ -62,6 +62,14 @@ default boolean visitContent() throws IOException {
 		return true;
 	}
 
+	// TODO: Un-"default" in the next breaking release
+	default boolean visitPackage(String srcName, @Nullable String[] dstNames) throws IOException {
+		return false;
+	}
+
+	// TODO: Un-"default" in the next breaking release
+	default void visitPackageComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException { }
+
 	boolean visitClass(String srcName, @Nullable String[] dstNames) throws IOException;
 	void visitClassComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException;
 
@@ -149,6 +157,17 @@ default boolean visitMethodVar(String srcClsName, String srcMethodName, @Nullabl
 	}
 
 	// convenience / potentially higher efficiency visit methods for only one dst name
+	default boolean visitPackage(String srcName, String dstName) throws IOException {
+		return visitPackage(srcName, toArray(dstName));
+	}
+
+	default void visitPackageComment(String srcName, String comment) throws IOException {
+		visitPackageComment(srcName, (String) null, comment);
+	}
+
+	default void visitPackageComment(String srcName, @Nullable String dstName, String comment) throws IOException {
+		visitPackageComment(srcName, toArray(dstName), comment);
+	}
 
 	default boolean visitClass(String srcName, String dstName) throws IOException {
 		return visitClass(srcName, toArray(dstName));
diff --git a/src/main/java/net/fabricmc/mappingio/MappedElementKind.java b/src/main/java/net/fabricmc/mappingio/MappedElementKind.java
index a046c5f1..6a7c8e8f 100644
--- a/src/main/java/net/fabricmc/mappingio/MappedElementKind.java
+++ b/src/main/java/net/fabricmc/mappingio/MappedElementKind.java
@@ -20,6 +20,7 @@
  * A kind of element that can be mapped.
  */
 public enum MappedElementKind {
+	PACKAGE(0),
 	CLASS(0),
 	FIELD(1),
 	METHOD(1),
diff --git a/src/main/java/net/fabricmc/mappingio/MappingVisitor.java b/src/main/java/net/fabricmc/mappingio/MappingVisitor.java
index 7dd01e12..d2920889 100644
--- a/src/main/java/net/fabricmc/mappingio/MappingVisitor.java
+++ b/src/main/java/net/fabricmc/mappingio/MappingVisitor.java
@@ -28,7 +28,8 @@
  * <p>The visitation order is as follows (omitting visit prefixes for brevity, lowercase for cross-references):
  * <ul><li>overall: header -> content -> End -> overall
  * <li>header: Header -> Namespaces [-> Metadata]*
- * <li>content: Content [-> class|Metadata]*
+ * <li>content: Content [-> package|class|Metadata]*
+ * <li>package: Package [-> DstName]* -> ElementContent [-> Comment]
  * <li>class: Class [-> DstName]* -> ElementContent [-> field|method|Comment]*
  * <li>field: Field [-> DstName|DstDesc]* -> ElementContent [-> Comment]
  * <li>method: Method [-> DstName|DstDesc]* -> ElementContent [-> arg|var|Comment]*
@@ -85,6 +86,18 @@ default boolean visitContent() throws IOException {
 		return true;
 	}
 
+	/**
+	 * Visit a package.
+	 *
+	 * @param srcName The package path, with slashes instead of dots, and no trailing slash.
+	 * An empty string represents the default package.
+	 * @return Whether the package's content should be visited too.
+	 */
+	// TODO: Un-"default" in the next breaking release
+	default boolean visitPackage(String srcName) throws IOException {
+		return false;
+	}
+
 	/**
 	 * Visit a class.
 	 *
diff --git a/src/main/java/net/fabricmc/mappingio/adapter/FlatAsRegularMappingVisitor.java b/src/main/java/net/fabricmc/mappingio/adapter/FlatAsRegularMappingVisitor.java
index 0ce63765..cca231e2 100644
--- a/src/main/java/net/fabricmc/mappingio/adapter/FlatAsRegularMappingVisitor.java
+++ b/src/main/java/net/fabricmc/mappingio/adapter/FlatAsRegularMappingVisitor.java
@@ -64,10 +64,11 @@ public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) thr
 		Set<MappingFlag> flags = next.getFlags();
 
 		if (flags.contains(MappingFlag.NEEDS_ELEMENT_UNIQUENESS)) {
+			dstPackageNames = new String[count];
 			dstClassNames = new String[count];
 			dstMemberNames = new String[count];
 		} else {
-			dstClassNames = dstMemberNames = null;
+			dstPackageNames = dstClassNames = dstMemberNames = null;
 		}
 
 		dstMemberDescs = flags.contains(MappingFlag.NEEDS_DST_FIELD_DESC) || flags.contains(MappingFlag.NEEDS_DST_METHOD_DESC) ? new String[count] : null;
@@ -83,6 +84,16 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		this.srcPkgName = srcName;
+
+		Arrays.fill(dstNames, null);
+		if (dstPackageNames != null) Arrays.fill(dstPackageNames, null);
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) {
 		this.srcClsName = srcName;
@@ -161,6 +172,10 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 		boolean relay;
 
 		switch (targetKind) {
+		case PACKAGE:
+			relay = next.visitPackage(srcPkgName, dstNames);
+			if (relay && dstPackageNames != null) System.arraycopy(dstNames, 0, dstPackageNames, 0, dstNames.length);
+			break;
 		case CLASS:
 			relay = next.visitClass(srcClsName, dstNames);
 			if (relay && dstClassNames != null) System.arraycopy(dstNames, 0, dstClassNames, 0, dstNames.length);
@@ -193,6 +208,9 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 	@Override
 	public void visitComment(MappedElementKind targetKind, String comment) throws IOException {
 		switch (targetKind) {
+		case PACKAGE:
+			next.visitPackageComment(srcPkgName, dstNames, comment);
+			break;
 		case CLASS:
 			next.visitClassComment(srcClsName, dstClassNames, comment);
 			break;
@@ -217,12 +235,14 @@ public void visitComment(MappedElementKind targetKind, String comment) throws IO
 
 	private final FlatMappingVisitor next;
 
+	private String srcPkgName;
 	private String srcClsName;
 	private String srcMemberName;
 	private String srcMemberDesc;
 	private String srcMemberSubName;
 	private int argIdx, lvIndex, startOpIdx, endOpIdx;
 	private String[] dstNames;
+	private String[] dstPackageNames;
 	private String[] dstClassNames;
 	private String[] dstMemberNames;
 	private String[] dstMemberDescs;
diff --git a/src/main/java/net/fabricmc/mappingio/adapter/ForwardingMappingVisitor.java b/src/main/java/net/fabricmc/mappingio/adapter/ForwardingMappingVisitor.java
index 876f9df1..838a6b87 100644
--- a/src/main/java/net/fabricmc/mappingio/adapter/ForwardingMappingVisitor.java
+++ b/src/main/java/net/fabricmc/mappingio/adapter/ForwardingMappingVisitor.java
@@ -69,6 +69,11 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		return next.visitPackage(srcName);
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		return next.visitClass(srcName);
diff --git a/src/main/java/net/fabricmc/mappingio/adapter/MappingNsCompleter.java b/src/main/java/net/fabricmc/mappingio/adapter/MappingNsCompleter.java
index 294721a7..683c1ea1 100644
--- a/src/main/java/net/fabricmc/mappingio/adapter/MappingNsCompleter.java
+++ b/src/main/java/net/fabricmc/mappingio/adapter/MappingNsCompleter.java
@@ -135,6 +135,13 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		this.srcName = srcName;
+
+		return next.visitPackage(srcName);
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		this.srcName = srcName;
diff --git a/src/main/java/net/fabricmc/mappingio/adapter/MappingSourceNsSwitch.java b/src/main/java/net/fabricmc/mappingio/adapter/MappingSourceNsSwitch.java
index 991bbc32..99ffa19f 100644
--- a/src/main/java/net/fabricmc/mappingio/adapter/MappingSourceNsSwitch.java
+++ b/src/main/java/net/fabricmc/mappingio/adapter/MappingSourceNsSwitch.java
@@ -142,6 +142,15 @@ public boolean visitContent() throws IOException {
 		return next.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		if (passThrough) return next.visitPackage(srcName);
+
+		this.srcName = srcName;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		if (passThrough) return next.visitClass(srcName);
@@ -256,6 +265,9 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 		boolean relay;
 
 		switch (targetKind) {
+		case PACKAGE:
+			relay = next.visitPackage(dstName);
+			break;
 		case CLASS:
 			relay = next.visitClass(dstName);
 			break;
diff --git a/src/main/java/net/fabricmc/mappingio/adapter/RegularAsFlatMappingVisitor.java b/src/main/java/net/fabricmc/mappingio/adapter/RegularAsFlatMappingVisitor.java
index 0e9abba6..a46a9f02 100644
--- a/src/main/java/net/fabricmc/mappingio/adapter/RegularAsFlatMappingVisitor.java
+++ b/src/main/java/net/fabricmc/mappingio/adapter/RegularAsFlatMappingVisitor.java
@@ -74,7 +74,38 @@ public boolean visitContent() throws IOException {
 	}
 
 	@Override
-	public boolean visitClass(String srcName, String[] dstNames) throws IOException {
+	public boolean visitPackage(String srcName, @Nullable String[] dstNames) throws IOException {
+		return visitPackage(srcName, dstNames, null);
+	}
+
+	@Override
+	public boolean visitPackage(String srcName, String dstName) throws IOException {
+		return visitPackage(srcName, null, dstName);
+	}
+
+	private boolean visitPackage(String srcName, @Nullable String[] dstNames, @Nullable String dstName) throws IOException {
+		if (!srcName.equals(lastPackage)) {
+			lastPackage = srcName;
+			relayLastPackage = next.visitPackage(srcName) && visitDstNames(MappedElementKind.PACKAGE, dstNames, dstName);
+		}
+
+		return relayLastPackage;
+	}
+
+	@Override
+	public void visitPackageComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException {
+		if (!visitPackage(srcName, dstNames, null)) return;
+		next.visitComment(MappedElementKind.PACKAGE, comment);
+	}
+
+	@Override
+	public void visitPackageComment(String srcName, @Nullable String dstName, String comment) throws IOException {
+		if (!visitPackage(srcName, null, dstName)) return;
+		next.visitComment(MappedElementKind.PACKAGE, comment);
+	}
+
+	@Override
+	public boolean visitClass(String srcName, @Nullable String[] dstNames) throws IOException {
 		return visitClass(srcName, dstNames, null);
 	}
 
@@ -367,6 +398,8 @@ private boolean visitDstNamesDescs(MappedElementKind targetKind, @Nullable Strin
 	private boolean relayDstFieldDescs;
 	private boolean relayDstMethodDescs;
 
+	private String lastPackage;
+	private boolean relayLastPackage;
 	private String lastClass;
 	private boolean relayLastClass;
 	private String lastMemberName, lastMemberDesc;
diff --git a/src/main/java/net/fabricmc/mappingio/format/FeatureSet.java b/src/main/java/net/fabricmc/mappingio/format/FeatureSet.java
index 4c3a78d8..b63d201e 100644
--- a/src/main/java/net/fabricmc/mappingio/format/FeatureSet.java
+++ b/src/main/java/net/fabricmc/mappingio/format/FeatureSet.java
@@ -20,7 +20,7 @@ public interface FeatureSet {
 	boolean hasNamespaces();
 	MetadataSupport fileMetadata();
 	MetadataSupport elementMetadata();
-	NameSupport packages();
+	PackageSupport packages();
 	ClassSupport classes();
 	MemberSupport fields();
 	MemberSupport methods();
@@ -30,13 +30,11 @@ public interface FeatureSet {
 	boolean hasFileComments();
 
 	default boolean supportsPackages() {
-		return packages().srcNames() != FeaturePresence.ABSENT
-				|| packages().dstNames() != FeaturePresence.ABSENT;
+		return packages().srcNames() != FeaturePresence.ABSENT;
 	}
 
 	default boolean supportsClasses() {
-		return classes().srcNames() != FeaturePresence.ABSENT
-				|| classes().dstNames() != FeaturePresence.ABSENT;
+		return classes().srcNames() != FeaturePresence.ABSENT;
 	}
 
 	default boolean supportsFields() {
@@ -82,6 +80,10 @@ interface DescSupport {
 		FeaturePresence dstDescs();
 	}
 
+	interface PackageSupport extends NameSupport {
+		boolean hasStructureModification();
+	}
+
 	interface ClassSupport extends NameSupport {
 		boolean hasRepackaging();
 	}
diff --git a/src/main/java/net/fabricmc/mappingio/format/FeatureSetBuilder.java b/src/main/java/net/fabricmc/mappingio/format/FeatureSetBuilder.java
index d6d399ad..4791e856 100644
--- a/src/main/java/net/fabricmc/mappingio/format/FeatureSetBuilder.java
+++ b/src/main/java/net/fabricmc/mappingio/format/FeatureSetBuilder.java
@@ -28,11 +28,13 @@
 import net.fabricmc.mappingio.format.FeatureSet.MemberSupport;
 import net.fabricmc.mappingio.format.FeatureSet.MetadataSupport;
 import net.fabricmc.mappingio.format.FeatureSet.NameSupport;
+import net.fabricmc.mappingio.format.FeatureSet.PackageSupport;
 import net.fabricmc.mappingio.format.FeatureSetImpl.ClassSupportImpl;
 import net.fabricmc.mappingio.format.FeatureSetImpl.DescSupportImpl;
 import net.fabricmc.mappingio.format.FeatureSetImpl.LocalSupportImpl;
 import net.fabricmc.mappingio.format.FeatureSetImpl.MemberSupportImpl;
 import net.fabricmc.mappingio.format.FeatureSetImpl.NameSupportImpl;
+import net.fabricmc.mappingio.format.FeatureSetImpl.PackageSupportImpl;
 
 @ApiStatus.Experimental
 public class FeatureSetBuilder {
@@ -45,7 +47,7 @@ public static FeatureSetBuilder createFrom(FeatureSet featureSet) {
 				featureSet.hasNamespaces(),
 				featureSet.fileMetadata(),
 				featureSet.elementMetadata(),
-				new NameFeatureBuilder(featureSet.packages()),
+				new PackageSupportBuilder(featureSet.packages()),
 				new ClassSupportBuilder(featureSet.classes()),
 				new MemberSupportBuilder(featureSet.fields()),
 				new MemberSupportBuilder(featureSet.methods()),
@@ -59,7 +61,7 @@ public static FeatureSetBuilder createFrom(FeatureSet featureSet) {
 		this(initWithFullSupport,
 				initWithFullSupport ? MetadataSupport.ARBITRARY : MetadataSupport.NONE,
 				initWithFullSupport ? MetadataSupport.ARBITRARY : MetadataSupport.NONE,
-				new NameFeatureBuilder(initWithFullSupport),
+				new PackageSupportBuilder(initWithFullSupport),
 				new ClassSupportBuilder(initWithFullSupport),
 				new MemberSupportBuilder(initWithFullSupport),
 				new MemberSupportBuilder(initWithFullSupport),
@@ -69,7 +71,7 @@ public static FeatureSetBuilder createFrom(FeatureSet featureSet) {
 				initWithFullSupport);
 	}
 
-	FeatureSetBuilder(boolean hasNamespaces, MetadataSupport fileMetadata, MetadataSupport elementMetadata, NameFeatureBuilder packages, ClassSupportBuilder classes, MemberSupportBuilder fields, MemberSupportBuilder methods, LocalSupportBuilder args, LocalSupportBuilder vars, ElementCommentSupport elementComments, boolean hasFileComments) {
+	FeatureSetBuilder(boolean hasNamespaces, MetadataSupport fileMetadata, MetadataSupport elementMetadata, PackageSupportBuilder packages, ClassSupportBuilder classes, MemberSupportBuilder fields, MemberSupportBuilder methods, LocalSupportBuilder args, LocalSupportBuilder vars, ElementCommentSupport elementComments, boolean hasFileComments) {
 		this.hasNamespaces = hasNamespaces;
 		this.fileMetadata = fileMetadata;
 		this.elementMetadata = elementMetadata;
@@ -98,7 +100,7 @@ public FeatureSetBuilder withElementMetadata(MetadataSupport featurePresence) {
 		return this;
 	}
 
-	public FeatureSetBuilder withPackages(Consumer<NameFeatureBuilder> featureApplier) {
+	public FeatureSetBuilder withPackages(Consumer<PackageSupportBuilder> featureApplier) {
 		featureApplier.accept(packages);
 		return this;
 	}
@@ -156,7 +158,7 @@ public FeatureSet build() {
 	private boolean hasNamespaces;
 	private MetadataSupport fileMetadata;
 	private MetadataSupport elementMetadata;
-	private NameFeatureBuilder packages;
+	private PackageSupportBuilder packages;
 	private ClassSupportBuilder classes;
 	private MemberSupportBuilder fields;
 	private MemberSupportBuilder methods;
@@ -165,6 +167,47 @@ public FeatureSet build() {
 	private ElementCommentSupport elementComments;
 	private boolean hasFileComments;
 
+	public static class PackageSupportBuilder {
+		PackageSupportBuilder() {
+			this(false);
+		}
+
+		PackageSupportBuilder(boolean initWithFullSupport) {
+			this(new NameFeatureBuilder(initWithFullSupport), initWithFullSupport);
+		}
+
+		PackageSupportBuilder(PackageSupport classFeature) {
+			this(new NameFeatureBuilder(classFeature), classFeature.hasStructureModification());
+		}
+
+		private PackageSupportBuilder(NameFeatureBuilder names, boolean hasStructureModification) {
+			this.names = names;
+			this.hasStructureModification = hasStructureModification;
+		}
+
+		public PackageSupportBuilder withSrcNames(FeaturePresence featurePresence) {
+			names.withSrcNames(featurePresence);
+			return this;
+		}
+
+		public PackageSupportBuilder withDstNames(FeaturePresence featurePresence) {
+			names.withDstNames(featurePresence);
+			return this;
+		}
+
+		public PackageSupportBuilder withStructureModification(boolean value) {
+			hasStructureModification = value;
+			return this;
+		}
+
+		public PackageSupport build() {
+			return new PackageSupportImpl(names.build(), hasStructureModification);
+		}
+
+		private NameFeatureBuilder names;
+		private boolean hasStructureModification;
+	}
+
 	public static class ClassSupportBuilder {
 		ClassSupportBuilder() {
 			this(false);
diff --git a/src/main/java/net/fabricmc/mappingio/format/FeatureSetImpl.java b/src/main/java/net/fabricmc/mappingio/format/FeatureSetImpl.java
index 30283a59..7e31c53c 100644
--- a/src/main/java/net/fabricmc/mappingio/format/FeatureSetImpl.java
+++ b/src/main/java/net/fabricmc/mappingio/format/FeatureSetImpl.java
@@ -17,7 +17,7 @@
 package net.fabricmc.mappingio.format;
 
 class FeatureSetImpl implements FeatureSet {
-	FeatureSetImpl(boolean hasNamespaces, MetadataSupport fileMetadata, MetadataSupport elementMetadata, NameSupport packages, ClassSupport classes, MemberSupport fields, MemberSupport methods, LocalSupport args, LocalSupport vars, ElementCommentSupport elementComments, boolean hasFileComments) {
+	FeatureSetImpl(boolean hasNamespaces, MetadataSupport fileMetadata, MetadataSupport elementMetadata, PackageSupport packages, ClassSupport classes, MemberSupport fields, MemberSupport methods, LocalSupport args, LocalSupport vars, ElementCommentSupport elementComments, boolean hasFileComments) {
 		this.hasNamespaces = hasNamespaces;
 		this.fileMetadata = fileMetadata;
 		this.elementMetadata = elementMetadata;
@@ -47,7 +47,7 @@ public MetadataSupport elementMetadata() {
 	}
 
 	@Override
-	public NameSupport packages() {
+	public PackageSupport packages() {
 		return packages;
 	}
 
@@ -89,7 +89,7 @@ public boolean hasFileComments() {
 	private final boolean hasNamespaces;
 	private final MetadataSupport fileMetadata;
 	private final MetadataSupport elementMetadata;
-	private final NameSupport packages;
+	private final PackageSupport packages;
 	private final ClassSupport classes;
 	private final MemberSupport fields;
 	private final MemberSupport methods;
@@ -98,6 +98,20 @@ public boolean hasFileComments() {
 	private final ElementCommentSupport elementComments;
 	private final boolean hasFileComments;
 
+	static class PackageSupportImpl extends NameSupportImpl implements PackageSupport {
+		PackageSupportImpl(NameSupport names, boolean hasStructureModification) {
+			super(names.srcNames(), names.dstNames());
+			this.hasStructureModification = hasStructureModification;
+		}
+
+		@Override
+		public boolean hasStructureModification() {
+			return hasStructureModification;
+		}
+
+		private final boolean hasStructureModification;
+	}
+
 	static class ClassSupportImpl extends NameSupportImpl implements ClassSupport {
 		ClassSupportImpl(NameSupport names, boolean hasRepackaging) {
 			super(names.srcNames(), names.dstNames());
diff --git a/src/main/java/net/fabricmc/mappingio/format/MappingFormat.java b/src/main/java/net/fabricmc/mappingio/format/MappingFormat.java
index b281ce36..79b9e0a0 100644
--- a/src/main/java/net/fabricmc/mappingio/format/MappingFormat.java
+++ b/src/main/java/net/fabricmc/mappingio/format/MappingFormat.java
@@ -137,13 +137,12 @@ public enum MappingFormat {
 
 	/**
 	 * The {@code SRG} ("Searge RetroGuard") mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L69-L81">here</a>.
-	 *
-	 * @implNote Package mappings are currently not supported.
 	 */
 	SRG_FILE("SRG file", "srg", true, FeatureSetBuilder.create()
 			.withPackages(p -> p
 					.withSrcNames(FeaturePresence.REQUIRED)
-					.withDstNames(FeaturePresence.REQUIRED))
+					.withDstNames(FeaturePresence.REQUIRED)
+					.withStructureModification(true))
 			.withClasses(c -> c
 					.withSrcNames(FeaturePresence.REQUIRED)
 					.withDstNames(FeaturePresence.REQUIRED)
@@ -162,8 +161,6 @@ public enum MappingFormat {
 	 * The {@code XSRG} ("Extended SRG") mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L69-L84">here</a>.
 	 *
 	 * <p>Same as SRG, but with field descriptors.
-	 *
-	 * @implNote Package mappings are currently not supported.
 	 */
 	XSRG_FILE("XSRG file", "xsrg", true, FeatureSetBuilder.createFrom(SRG_FILE.features)
 			.withFields(f -> f
@@ -176,7 +173,8 @@ public enum MappingFormat {
 	JAM_FILE("JAM file", "jam", true, FeatureSetBuilder.createFrom(SRG_FILE.features)
 			.withPackages(p -> p
 					.withSrcNames(FeaturePresence.ABSENT)
-					.withDstNames(FeaturePresence.ABSENT))
+					.withDstNames(FeaturePresence.ABSENT)
+					.withStructureModification(false))
 			.withFields(f -> f
 					.withSrcDescs(FeaturePresence.REQUIRED))
 			.withMethods(m -> m
@@ -188,8 +186,6 @@ public enum MappingFormat {
 
 	/**
 	 * The {@code CSRG} ("Compact SRG", since it saves disk space over SRG) mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L196-L207">here</a>.
-	 *
-	 * @implNote Package mappings are currently not supported.
 	 */
 	CSRG_FILE("CSRG file", "csrg", true, FeatureSetBuilder.createFrom(SRG_FILE.features)
 			.withMethods(m -> m
@@ -199,15 +195,13 @@ public enum MappingFormat {
 	 * The {@code TSRG} ("Tiny SRG", since it saves disk space over SRG) mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L196-L213">here</a>.
 	 *
 	 * <p>Same as CSRG, but hierarchical instead of flat.
-	 *
-	 * @implNote Package mappings are currently not supported.
 	 */
 	TSRG_FILE("TSRG file", "tsrg", true, FeatureSetBuilder.createFrom(CSRG_FILE.features)),
 
 	/**
 	 * The {@code TSRG v2} mapping format, as specified <a href="https://github.com/MinecraftForge/SrgUtils/blob/67f30647ece29f18256ca89a23cda6216d6bd21e/src/main/java/net/minecraftforge/srgutils/InternalUtils.java#L262-L285">here</a>.
 	 *
-	 * @implNote Package mappings and static markers for methods are currently not supported.
+	 * @implNote Static method markers are currently not supported.
 	 */
 	TSRG_2_FILE("TSRG v2 file", "tsrg", true, FeatureSetBuilder.createFrom(TSRG_FILE.features)
 			.withNamespaces(true)
@@ -222,13 +216,14 @@ public enum MappingFormat {
 	/**
 	 * The IntelliJ IDEA migration map format, as implemented <a href="https://github.com/JetBrains/intellij-community/tree/5b6191dd34e05de8897f5da68757146395a260cc/java/java-impl-refactorings/src/com/intellij/refactoring/migration">here</a>.
 	 *
-	 * @implNote Package mappings and file metadata are currently not supported.
+	 * @implNote File metadata is currently not supported.
 	 */
 	INTELLIJ_MIGRATION_MAP_FILE("IntelliJ migration map file", "xml", true, FeatureSetBuilder.create()
 			.withFileMetadata(MetadataSupport.FIXED) // migration map name and description
 			.withPackages(p -> p
 					.withSrcNames(FeaturePresence.REQUIRED)
-					.withDstNames(FeaturePresence.REQUIRED))
+					.withDstNames(FeaturePresence.REQUIRED)
+					.withStructureModification(true))
 			.withClasses(c -> c
 					.withSrcNames(FeaturePresence.REQUIRED)
 					.withDstNames(FeaturePresence.REQUIRED)
@@ -255,8 +250,6 @@ public enum MappingFormat {
 
 	/**
 	 * The {@code JOBF} mapping format, as implemented <a href="https://github.com/skylot/jadx/blob/2d5c0fda4a0c5d16207a5f48edb72e6efa7d5bbd/jadx-core/src/main/java/jadx/core/deobf/DeobfPresets.java">here</a>.
-	 *
-	 * @implNote Package mappings are currently not supported.
 	 */
 	JOBF_FILE("JOBF file", "jobf", true, FeatureSetBuilder.create()
 			.withPackages(p -> p
diff --git a/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileReader.java b/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileReader.java
index 1148c177..02547d5d 100644
--- a/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileReader.java
+++ b/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileReader.java
@@ -122,14 +122,17 @@ private static void read0(BufferedReader reader, String sourceNs, String targetN
 							break;
 						case "entry":
 							String type = xmlReader.getAttributeValue(null, "type");
+							boolean isPackage;
 
 							if (type == null || type.isEmpty()) throw new IOException("missing/empty type attribute at line "+xmlReader.getLocation().getLineNumber());
-							if (type.equals("package")) continue; // TODO: support packages
-							if (!type.equals("class")) throw new IOException("unexpected entry type "+type+" at line "+xmlReader.getLocation().getLineNumber());
+
+							if (!(isPackage = type.equals("package")) && !type.equals("class")) {
+								throw new IOException("unexpected entry type "+type+" at line "+xmlReader.getLocation().getLineNumber());
+							}
 
 							String srcName = xmlReader.getAttributeValue(null, "oldName");
 							String dstName = xmlReader.getAttributeValue(null, "newName");
-							// String recursive = xmlReader.getAttributeValue(null, "recursive"); // only used for packages
+							// String recursive = xmlReader.getAttributeValue(null, "recursive"); // only used for packages, indicates if subpackages should also be renamed
 
 							if (srcName == null || srcName.isEmpty()) throw new IOException("missing/empty oldName attribute at line "+xmlReader.getLocation().getLineNumber());
 							if (dstName == null || dstName.isEmpty()) throw new IOException("missing/empty newName attribute at line "+xmlReader.getLocation().getLineNumber());
@@ -137,7 +140,11 @@ private static void read0(BufferedReader reader, String sourceNs, String targetN
 							srcName = srcName.replace('.', '/');
 							dstName = dstName.replace('.', '/');
 
-							if (visitor.visitClass(srcName)) {
+							if (isPackage && visitor.visitPackage(srcName)) {
+								visitor.visitDstName(MappedElementKind.PACKAGE, 0, dstName);
+								visitor.visitElementContent(MappedElementKind.PACKAGE);
+								// TODO: visit "recursive" attribute as element metadata once https://github.com/FabricMC/mapping-io/pull/41 is merged
+							} else if (!isPackage && visitor.visitClass(srcName)) {
 								visitor.visitDstName(MappedElementKind.CLASS, 0, dstName);
 								visitor.visitElementContent(MappedElementKind.CLASS);
 							}
diff --git a/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileWriter.java b/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileWriter.java
index 95c9b5e2..181ac974 100644
--- a/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileWriter.java
+++ b/src/main/java/net/fabricmc/mappingio/format/intellij/MigrationMapFileWriter.java
@@ -122,10 +122,20 @@ public void visitMetadata(String key, @Nullable String value) throws IOException
 		}
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		this.srcName = srcName;
+		this.dstName = null;
+		this.isPackage = true;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		this.srcName = srcName;
 		this.dstName = null;
+		this.isPackage = false;
 
 		return true;
 	}
@@ -166,7 +176,11 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 			xmlWriter.writeEmptyElement("entry");
 			xmlWriter.writeAttribute("oldName", srcName.replace('/', '.'));
 			xmlWriter.writeAttribute("newName", dstName.replace('/', '.'));
-			xmlWriter.writeAttribute("type", "class");
+			xmlWriter.writeAttribute("type", isPackage ? "package" : "class");
+
+			if (isPackage) {
+				xmlWriter.writeAttribute("recursive", "false"); // TODO: true or false?
+			}
 		} catch (XMLStreamException e) {
 			throw new IOException(e);
 		}
@@ -185,6 +199,7 @@ public void visitComment(MappedElementKind targetKind, String comment) throws IO
 	private XMLStreamWriter xmlWriter;
 	private boolean wroteName;
 	private boolean wroteOrder;
+	private boolean isPackage;
 	private String srcName;
 	private String dstName;
 }
diff --git a/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileReader.java b/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileReader.java
index e3a13489..b4828eb5 100644
--- a/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileReader.java
+++ b/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileReader.java
@@ -73,7 +73,21 @@ private static void read(ColumnFileReader reader, String sourceNs, String target
 				do {
 					boolean isField;
 
-					if (reader.nextCol("c")) { // class: c <pkg>.<cls-name-a> = <cls-name-b>
+					if (reader.nextCol("p")) { // package: p <name-a> = <name-b>
+						String srcName = reader.nextCol();
+						if (srcName == null || srcName.isEmpty()) throw new IOException("missing package-name-a in line "+reader.getLineNumber());
+						srcName = srcName.replace('.', '/');
+
+						if (visitor.visitPackage(srcName)) {
+							readSeparator(reader);
+
+							String dstName = reader.nextCol();
+							if (dstName == null || dstName.isEmpty()) throw new IOException("missing package-name-b in line "+reader.getLineNumber());
+
+							visitor.visitDstName(MappedElementKind.PACKAGE, 0, dstName.replace('.', '/'));
+							visitor.visitElementContent(MappedElementKind.PACKAGE);
+						}
+					} else if (reader.nextCol("c")) { // class: c <pkg>.<cls-name-a> = <cls-name-b>
 						String srcName = reader.nextCol();
 						if (srcName == null || srcName.isEmpty()) throw new IOException("missing class-name-a in line "+reader.getLineNumber());
 						srcName = srcName.replace('.', '/');
@@ -128,8 +142,6 @@ private static void read(ColumnFileReader reader, String sourceNs, String target
 								visitor.visitElementContent(kind);
 							}
 						}
-					} else if (reader.nextCol("p")) { // package: p <name-a> = <name-b>
-						// TODO
 					}
 				} while (reader.nextLine(0));
 			}
diff --git a/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileWriter.java b/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileWriter.java
index 39af0dbe..c8c497b8 100644
--- a/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileWriter.java
+++ b/src/main/java/net/fabricmc/mappingio/format/jobf/JobfFileWriter.java
@@ -51,6 +51,14 @@ public Set<MappingFlag> getFlags() {
 	public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) throws IOException {
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		packageSrcName = srcName;
+		dstName = null;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		classSrcName = srcName;
@@ -104,12 +112,23 @@ public void visitDstName(MappedElementKind targetKind, int namespace, String nam
 
 	@Override
 	public boolean visitElementContent(MappedElementKind targetKind) throws IOException {
+		boolean isPackage = targetKind == MappedElementKind.PACKAGE;
 		boolean isClass = targetKind == MappedElementKind.CLASS;
 		boolean isField = false;
 
-		if (dstName == null) return isClass;
+		if (dstName == null) {
+			return isPackage || isClass;
+		}
 
-		if ((isClass)) {
+		if (isPackage) {
+			if (countOccurrences(packageSrcName, '/') != countOccurrences(dstName, '/')) {
+				return false; // JOBF doesn't allow changes to the package structure
+			}
+
+			packageSrcName = packageSrcName.replace('/', '.');
+			dstName = dstName.replace('/', '.');
+			write("p ");
+		} else if (isClass) {
 			int srcNameLastSep = classSrcName.lastIndexOf('/');
 			int dstNameLastSep = dstName.lastIndexOf('/');
 			String srcPkg = classSrcName.substring(0, srcNameLastSep + 1);
@@ -127,9 +146,9 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 			throw new IllegalStateException("unexpected invocation for "+targetKind);
 		}
 
-		write(classSrcName);
+		write(isPackage ? packageSrcName : classSrcName);
 
-		if (!isClass) {
+		if (!isPackage && !isClass) {
 			write(".");
 			write(memberSrcName);
 
@@ -158,9 +177,20 @@ private void writeLn() throws IOException {
 		writer.write('\n');
 	}
 
+	private int countOccurrences(String str, char c) {
+		int count = 0;
+
+		for (int i = 0; i < str.length(); i++) {
+			if (str.charAt(i) == c) count++;
+		}
+
+		return count;
+	}
+
 	private static final Set<MappingFlag> flags = EnumSet.of(MappingFlag.NEEDS_SRC_FIELD_DESC, MappingFlag.NEEDS_SRC_METHOD_DESC);
 
 	private final Writer writer;
+	private String packageSrcName;
 	private String classSrcName;
 	private String memberSrcName;
 	private String memberSrcDesc;
diff --git a/src/main/java/net/fabricmc/mappingio/format/srg/CsrgFileWriter.java b/src/main/java/net/fabricmc/mappingio/format/srg/CsrgFileWriter.java
index 50ceedbb..4cb51e1b 100644
--- a/src/main/java/net/fabricmc/mappingio/format/srg/CsrgFileWriter.java
+++ b/src/main/java/net/fabricmc/mappingio/format/srg/CsrgFileWriter.java
@@ -52,6 +52,13 @@ public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) thr
 		// not supported, skip
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		packageSrcName = srcName + "/";
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		classSrcName = srcName;
@@ -92,15 +99,22 @@ public boolean visitMethodVar(int lvtRowIndex, int lvIndex, int startOpIdx, int
 	public void visitDstName(MappedElementKind targetKind, int namespace, String name) {
 		if (namespace != 0) return;
 
+		if (targetKind == MappedElementKind.PACKAGE && name != null) {
+			name += "/";
+		}
+
 		dstName = name;
 	}
 
 	@Override
 	public boolean visitElementContent(MappedElementKind targetKind) throws IOException {
 		if (dstName != null) {
-			write(classSrcName);
+			boolean isPackage = targetKind == MappedElementKind.PACKAGE;
+			boolean isClass = targetKind == MappedElementKind.CLASS;
+
+			write(isPackage ? packageSrcName : classSrcName);
 
-			if (targetKind != MappedElementKind.CLASS) {
+			if (!isPackage && !isClass) {
 				writeSpace();
 				write(memberSrcName);
 
@@ -114,8 +128,8 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 
 			writeSpace();
 			write(dstName);
-			writeLn();
 
+			writeLn();
 			dstName = null;
 		}
 
@@ -142,6 +156,7 @@ private void writeLn() throws IOException {
 	private static final Set<MappingFlag> flags = EnumSet.of(MappingFlag.NEEDS_SRC_METHOD_DESC);
 
 	private final Writer writer;
+	private String packageSrcName;
 	private String classSrcName;
 	private String memberSrcName;
 	private String methodSrcDesc;
diff --git a/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileReader.java b/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileReader.java
index 7884b41a..b952e315 100644
--- a/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileReader.java
+++ b/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileReader.java
@@ -76,7 +76,23 @@ private static void read(ColumnFileReader reader, String sourceNs, String target
 				do {
 					boolean isMethod;
 
-					if (reader.nextCol("CL:")) { // class: CL: <src> <dst>
+					if (reader.nextCol("PK:")) { // package: PK: <src>/ <dst>/
+						String srcName = reader.nextCol();
+						if (srcName == null || srcName.isEmpty()) throw new IOException("missing package-name-a in line "+reader.getLineNumber());
+
+						if (classContentVisitPending) {
+							visitor.visitElementContent(MappedElementKind.CLASS);
+							classContentVisitPending = false;
+						}
+
+						if (visitor.visitPackage(srcName.substring(0, srcName.length() - 1))) {
+							String dstName = reader.nextCol();
+							if (dstName == null || dstName.isEmpty()) throw new IOException("missing package-name-b in line "+reader.getLineNumber());
+
+							visitor.visitDstName(MappedElementKind.PACKAGE, 0, dstName.substring(0, dstName.length() - 1));
+							visitor.visitElementContent(MappedElementKind.PACKAGE);
+						}
+					} else if (reader.nextCol("CL:")) { // class: CL: <src> <dst>
 						String srcName = reader.nextCol();
 						if (srcName == null || srcName.isEmpty()) throw new IOException("missing class-name-a in line "+reader.getLineNumber());
 
diff --git a/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileWriter.java b/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileWriter.java
index 84251990..e62efc4d 100644
--- a/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileWriter.java
+++ b/src/main/java/net/fabricmc/mappingio/format/srg/SrgFileWriter.java
@@ -53,6 +53,14 @@ public Set<MappingFlag> getFlags() {
 	public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) throws IOException {
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		packageSrcName = srcName + "/";
+		packageDstName = null;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		classSrcName = srcName;
@@ -104,6 +112,9 @@ public void visitDstName(MappedElementKind targetKind, int namespace, String nam
 		if (namespace != 0) return;
 
 		switch (targetKind) {
+		case PACKAGE:
+			packageDstName = name == null ? null : name + "/";
+			break;
 		case CLASS:
 			classDstName = name;
 			break;
@@ -125,9 +136,18 @@ public void visitDstDesc(MappedElementKind targetKind, int namespace, String des
 
 	@Override
 	public boolean visitElementContent(MappedElementKind targetKind) throws IOException {
+		boolean isPackage = false;
+		boolean isClass = false;
+
 		switch (targetKind) {
+		case PACKAGE:
+			if (packageDstName == null) return false;
+			isPackage = true;
+			write("PK: ");
+			break;
 		case CLASS:
 			if (classDstName == null) return true;
+			isClass = true;
 			write("CL: ");
 			break;
 		case FIELD:
@@ -142,9 +162,9 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 			throw new IllegalStateException("unexpected invocation for "+targetKind);
 		}
 
-		write(classSrcName);
+		write(isPackage ? packageSrcName : classSrcName);
 
-		if (targetKind != MappedElementKind.CLASS) {
+		if (!isPackage && !isClass) {
 			write("/");
 			write(memberSrcName);
 
@@ -155,10 +175,11 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 		}
 
 		write(" ");
-		if (classDstName == null) classDstName = classSrcName;
-		write(classDstName);
+		write(isPackage
+				? packageDstName != null ? packageDstName : packageSrcName
+				: classDstName != null ? classDstName : classSrcName);
 
-		if (targetKind != MappedElementKind.CLASS) {
+		if (!isPackage && !isClass) {
 			write("/");
 			write(memberDstName);
 
@@ -170,7 +191,7 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 
 		writeLn();
 
-		return targetKind == MappedElementKind.CLASS; // only members are supported, skip anything but class contents
+		return targetKind == MappedElementKind.CLASS; // skip anything but members
 	}
 
 	@Override
@@ -197,9 +218,11 @@ private void writeLn() throws IOException {
 
 	private final Writer writer;
 	private final boolean xsrg;
+	private String packageSrcName;
 	private String classSrcName;
 	private String memberSrcName;
 	private String memberSrcDesc;
+	private String packageDstName;
 	private String classDstName;
 	private String memberDstName;
 	private String memberDstDesc;
diff --git a/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileReader.java b/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileReader.java
index fdad07a9..2a59b8cd 100644
--- a/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileReader.java
+++ b/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileReader.java
@@ -128,7 +128,7 @@ private static void read(ColumnFileReader reader, String sourceNs, String target
 					reader.discardMark();
 					String[] parts = line.split("((?<= )|(?= ))"); // Split on spaces, but keep them
 
-					if (format != MappingFormat.TSRG_2_FILE && parts.length >= 4 && !parts[3].startsWith("#")) { // CSRG
+					if (format != MappingFormat.TSRG_2_FILE && parts.length >= 4 && !parts[3].startsWith("#")) { // CSRG member
 						format = MappingFormat.CSRG_FILE;
 						String clsName = parts[0];
 						if (clsName.isEmpty()) throw new IOException("missing class-name-a in line "+reader.getLineNumber());
@@ -173,14 +173,19 @@ private static void read(ColumnFileReader reader, String sourceNs, String target
 					}
 
 					String srcName = reader.nextCol();
-					if (srcName == null || srcName.endsWith("/")) continue;
-					if (srcName.isEmpty()) throw new IOException("missing class-name-a in line "+reader.getLineNumber());
+					if (srcName == null || srcName.isEmpty()) throw new IOException("missing package-/class-name-a in line "+reader.getLineNumber());
 
-					lastClass = srcName;
-					visitLastClass = visitor.visitClass(srcName);
+					if (srcName.endsWith("/")) { // package
+						if (visitor.visitPackage(srcName.substring(0, srcName.length() - 1))) {
+							readElement(reader, MappedElementKind.PACKAGE, 0, dstNsCount, visitor);
+						}
+					} else { // class
+						lastClass = srcName;
+						visitLastClass = visitor.visitClass(srcName);
 
-					if (visitLastClass) {
-						visitLastClass = readClass(reader, format == MappingFormat.TSRG_2_FILE, dstNsCount, nameTmp, visitor);
+						if (visitLastClass) {
+							visitLastClass = readClass(reader, format == MappingFormat.TSRG_2_FILE, dstNsCount, nameTmp, visitor);
+						}
 					}
 				} while (reader.nextLine(0));
 			}
@@ -299,6 +304,10 @@ private static void readDstNames(ColumnFileReader reader, MappedElementKind subj
 			if (name == null) throw new IOException("missing name columns in line "+reader.getLineNumber());
 			if (name.isEmpty()) throw new IOException("missing destination name in line "+reader.getLineNumber());
 
+			if (subjectKind == MappedElementKind.PACKAGE) {
+				name = name.substring(0, name.length() - 1);
+			}
+
 			visitor.visitDstName(subjectKind, dstNs, name);
 		}
 	}
diff --git a/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileWriter.java b/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileWriter.java
index 1536914b..1d289cbd 100644
--- a/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileWriter.java
+++ b/src/main/java/net/fabricmc/mappingio/format/srg/TsrgFileWriter.java
@@ -72,6 +72,14 @@ public void visitMetadata(String key, @Nullable String value) throws IOException
 		// TODO: Support the static method marker once https://github.com/FabricMC/mapping-io/pull/41 is merged
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		pkgSrcName = srcName += "/";
+		hasAnyDstNames = false;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		clsSrcName = srcName;
@@ -124,6 +132,10 @@ public boolean visitMethodVar(int lvtRowIndex, int lvIndex, int startOpIdx, int
 	public void visitDstName(MappedElementKind targetKind, int namespace, String name) {
 		if (!tsrg2 && namespace != 0) return;
 
+		if (targetKind == MappedElementKind.PACKAGE && name != null) {
+			name += "/";
+		}
+
 		dstNames[namespace] = name;
 		hasAnyDstNames |= name != null;
 	}
@@ -131,11 +143,11 @@ public void visitDstName(MappedElementKind targetKind, int namespace, String nam
 	@Override
 	public boolean visitElementContent(MappedElementKind targetKind) throws IOException {
 		if (classContentVisitPending && targetKind != MappedElementKind.CLASS && hasAnyDstNames) {
-			String[] memberOrArgDstNames = dstNames.clone();
+			String[] packageOrMemberOrArgDstNames = dstNames.clone();
 			Arrays.fill(dstNames, clsSrcName);
 			visitElementContent(MappedElementKind.CLASS);
 			classContentVisitPending = false;
-			dstNames = memberOrArgDstNames;
+			dstNames = packageOrMemberOrArgDstNames;
 		}
 
 		if (methodContentVisitPending && targetKind == MappedElementKind.METHOD_ARG && hasAnyDstNames) {
@@ -149,6 +161,10 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 		String srcName = null;
 
 		switch (targetKind) {
+		case PACKAGE:
+			if (!hasAnyDstNames) return false;
+			srcName = pkgSrcName;
+			break;
 		case CLASS:
 			if (!hasAnyDstNames) {
 				classContentVisitPending = true;
@@ -204,8 +220,7 @@ public boolean visitElementContent(MappedElementKind targetKind) throws IOExcept
 
 		Arrays.fill(dstNames, null);
 
-		return targetKind == MappedElementKind.CLASS
-				|| (tsrg2 && targetKind == MappedElementKind.METHOD);
+		return targetKind == MappedElementKind.CLASS || (tsrg2 && targetKind == MappedElementKind.METHOD);
 	}
 
 	@Override
@@ -239,6 +254,7 @@ private void writeLn() throws IOException {
 
 	private final Writer writer;
 	private final boolean tsrg2;
+	private String pkgSrcName;
 	private String clsSrcName;
 	private String memberSrcName;
 	private String memberSrcDesc;
diff --git a/src/main/java/net/fabricmc/mappingio/tree/MappingTree.java b/src/main/java/net/fabricmc/mappingio/tree/MappingTree.java
index a24de62d..5a184b8d 100644
--- a/src/main/java/net/fabricmc/mappingio/tree/MappingTree.java
+++ b/src/main/java/net/fabricmc/mappingio/tree/MappingTree.java
@@ -84,6 +84,34 @@ public interface MappingTree extends MappingTreeView {
 	 */
 	boolean removeMetadata(String key);
 
+	@Override
+	Collection<? extends PackageMapping> getPackages();
+	@Override
+	@Nullable
+	PackageMapping getPackage(String srcName);
+
+	@Override
+	@Nullable
+	default PackageMapping getPackage(String name, int namespace) {
+		return (PackageMapping) MappingTreeView.super.getPackage(name, namespace);
+	}
+
+	/**
+	 * Merges a package mapping into the tree.
+	 *
+	 * @return The {@link PackageMapping} instance present in the tree after the merge has occurred.
+	 * May or may not be the passed instance.
+	 */
+	PackageMapping addPackage(PackageMapping pkg);
+
+	/**
+	 * Removes a package mapping from the tree.
+	 *
+	 * @return The removed package mapping, if any.
+	 */
+	@Nullable
+	PackageMapping removePackage(String srcName);
+
 	@Override
 	Collection<? extends ClassMapping> getClasses();
 	@Override
@@ -227,6 +255,8 @@ interface ElementMapping extends ElementMappingView {
 		void setComment(String comment);
 	}
 
+	interface PackageMapping extends ElementMapping, PackageMappingView { }
+
 	interface ClassMapping extends ElementMapping, ClassMappingView {
 		@Override
 		Collection<? extends FieldMapping> getFields();
diff --git a/src/main/java/net/fabricmc/mappingio/tree/MappingTreeView.java b/src/main/java/net/fabricmc/mappingio/tree/MappingTreeView.java
index 3dacb7b1..b562f739 100644
--- a/src/main/java/net/fabricmc/mappingio/tree/MappingTreeView.java
+++ b/src/main/java/net/fabricmc/mappingio/tree/MappingTreeView.java
@@ -85,6 +85,20 @@ default String getNamespaceName(int id) {
 	 */
 	List<? extends MetadataEntryView> getMetadata(String key);
 
+	Collection<? extends PackageMappingView> getPackages();
+	@Nullable
+	PackageMappingView getPackage(String srcName);
+	@Nullable
+	default PackageMappingView getPackage(String name, int namespace) {
+		if (namespace < 0) return getPackage(name);
+
+		for (PackageMappingView pkg : getPackages()) {
+			if (name.equals(pkg.getDstName(namespace))) return pkg;
+		}
+
+		return null;
+	}
+
 	Collection<? extends ClassMappingView> getClasses();
 	@Nullable
 	ClassMappingView getClass(String srcName);
@@ -138,6 +152,23 @@ default void accept(MappingVisitor visitor) throws IOException {
 
 	void accept(MappingVisitor visitor, VisitOrder order) throws IOException;
 
+	default String mapPackageName(String name, int namespace) {
+		return mapPackageName(name, SRC_NAMESPACE_ID, namespace);
+	}
+
+	default String mapPackageName(String name, int srcNamespace, int dstNamespace) {
+		assert name.indexOf('.') < 0;
+
+		if (srcNamespace == dstNamespace) return name;
+
+		PackageMappingView pkg = getPackage(name, srcNamespace);
+		if (pkg == null) return name;
+
+		String ret = pkg.getName(dstNamespace);
+
+		return ret != null ? ret : name;
+	}
+
 	default String mapClassName(String name, int namespace) {
 		return mapClassName(name, SRC_NAMESPACE_ID, namespace);
 	}
@@ -247,6 +278,8 @@ default String getName(String namespace) {
 		String getComment();
 	}
 
+	interface PackageMappingView extends ElementMappingView { }
+
 	interface ClassMappingView extends ElementMappingView {
 		Collection<? extends FieldMappingView> getFields();
 
diff --git a/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java b/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java
index 67f5c03a..1dca8610 100644
--- a/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java
+++ b/src/main/java/net/fabricmc/mappingio/tree/MemoryMappingTree.java
@@ -68,13 +68,17 @@ public MemoryMappingTree(MappingTree src) {
 			addMetadata(entry);
 		}
 
+		for (PackageMapping pkg : src.getPackages()) {
+			addPackage(pkg);
+		}
+
 		for (ClassMapping cls : src.getClasses()) {
 			addClass(cls);
 		}
 	}
 
 	/**
-	 * Whether to index classes by their destination names, in addition to their source names.
+	 * Whether to index packages and classes by their destination names, in addition to their source names.
 	 *
 	 * <p>Trades higher memory consumption for faster lookups by destination name.
 	 */
@@ -83,14 +87,32 @@ public void setIndexByDstNames(boolean indexByDstNames) {
 		if (indexByDstNames == this.indexByDstNames) return;
 
 		if (!indexByDstNames) {
+			packagesByDstNames = null;
 			classesByDstNames = null;
 		} else if (dstNamespaces != null) {
+			initPackagesByDstNames();
 			initClassesByDstNames();
 		}
 
 		this.indexByDstNames = indexByDstNames;
 	}
 
+	@SuppressWarnings("unchecked")
+	private void initPackagesByDstNames() {
+		packagesByDstNames = new Map[dstNamespaces.size()];
+
+		for (int i = 0; i < packagesByDstNames.length; i++) {
+			packagesByDstNames[i] = new HashMap<String, PackageEntry>(packagesBySrcName.size());
+		}
+
+		for (PackageEntry pkg : packagesBySrcName.values()) {
+			for (int i = 0; i < pkg.dstNames.length; i++) {
+				String dstName = pkg.dstNames[i];
+				if (dstName != null) packagesByDstNames[i].put(dstName, pkg);
+			}
+		}
+	}
+
 	@SuppressWarnings("unchecked")
 	private void initClassesByDstNames() {
 		classesByDstNames = new Map[dstNamespaces.size()];
@@ -159,7 +181,7 @@ public List<String> getDstNamespaces() {
 	public List<String> setDstNamespaces(List<String> namespaces) {
 		assertNotInVisitPass();
 
-		if (!classesBySrcName.isEmpty()) { // classes present, update existing dstNames
+		if (!packagesBySrcName.isEmpty() || !classesBySrcName.isEmpty()) { // packages or classes present, update existing dstNames
 			int newSize = namespaces.size();
 			int[] nameMap = new int[newSize];
 			Set<String> processedNamespaces = new HashSet<>(newSize);
@@ -211,6 +233,7 @@ public List<String> setDstNamespaces(List<String> namespaces) {
 		dstNamespaces = namespaces;
 
 		if (indexByDstNames) {
+			initPackagesByDstNames();
 			initClassesByDstNames();
 		}
 
@@ -218,6 +241,10 @@ public List<String> setDstNamespaces(List<String> namespaces) {
 	}
 
 	private void resizeDstNames(int newSize) {
+		for (PackageEntry pkg : packagesBySrcName.values()) {
+			pkg.resizeDstNames(newSize);
+		}
+
 		for (ClassEntry cls : classesBySrcName.values()) {
 			cls.resizeDstNames(newSize);
 
@@ -240,6 +267,10 @@ private void resizeDstNames(int newSize) {
 	}
 
 	private void updateDstNames(int[] nameMap) {
+		for (PackageEntry pkg : packagesBySrcName.values()) {
+			pkg.updateDstNames(nameMap);
+		}
+
 		for (ClassEntry cls : classesBySrcName.values()) {
 			cls.updateDstNames(nameMap);
 
@@ -261,6 +292,13 @@ private void updateDstNames(int[] nameMap) {
 		}
 	}
 
+	private int getSrcNsEquivalent(ElementMapping mapping) {
+		int ret = mapping.getTree().getNamespaceId(srcNamespace);
+		if (ret == NULL_NAMESPACE_ID) throw new UnsupportedOperationException("can't find source namespace in referenced mapping tree");
+
+		return ret;
+	}
+
 	@Override
 	public List<? extends MetadataEntry> getMetadata() {
 		return metadata;
@@ -283,6 +321,64 @@ public boolean removeMetadata(String key) {
 		return metadata.removeIf(entry -> entry.getKey().equals(key));
 	}
 
+	@Override
+	public Collection<? extends PackageMapping> getPackages() {
+		return packagesView;
+	}
+
+	@Override
+	@Nullable
+	public PackageMapping getPackage(String srcName) {
+		return packagesBySrcName.get(srcName);
+	}
+
+	@Override
+	@Nullable
+	public PackageMapping getPackage(String name, int namespace) {
+		if (namespace < 0 || !indexByDstNames) {
+			return VisitableMappingTree.super.getPackage(name, namespace);
+		} else {
+			return packagesByDstNames[namespace].get(name);
+		}
+	}
+
+	@Override
+	public PackageMapping addPackage(PackageMapping pkg) {
+		assertNotInVisitPass();
+		PackageEntry entry = pkg instanceof PackageEntry && pkg.getTree() == this ? (PackageEntry) pkg : new PackageEntry(this, pkg, getSrcNsEquivalent(pkg));
+		PackageEntry ret = packagesBySrcName.putIfAbsent(pkg.getSrcName(), entry);
+
+		if (ret != null) {
+			ret.copyFrom(entry, true);
+			entry = ret;
+		}
+
+		if (indexByDstNames) {
+			for (int i = 0; i < entry.dstNames.length; i++) {
+				String dstName = entry.dstNames[i];
+				if (dstName != null) packagesByDstNames[i].put(dstName, entry);
+			}
+		}
+
+		return entry;
+	}
+
+	@Override
+	@Nullable
+	public PackageMapping removePackage(String srcName) {
+		assertNotInVisitPass();
+		PackageEntry ret = packagesBySrcName.remove(srcName);
+
+		if (ret != null && indexByDstNames) {
+			for (int i = 0; i < ret.dstNames.length; i++) {
+				String dstName = ret.dstNames[i];
+				if (dstName != null) packagesByDstNames[i].remove(dstName);
+			}
+		}
+
+		return ret;
+	}
+
 	@Override
 	public Collection<? extends ClassMapping> getClasses() {
 		return classesView;
@@ -325,13 +421,6 @@ public ClassMapping addClass(ClassMapping cls) {
 		return entry;
 	}
 
-	private int getSrcNsEquivalent(ElementMapping mapping) {
-		int ret = mapping.getTree().getNamespaceId(srcNamespace);
-		if (ret == NULL_NAMESPACE_ID) throw new UnsupportedOperationException("can't find source namespace in referenced mapping tree");
-
-		return ret;
-	}
-
 	@Override
 	@Nullable
 	public ClassMapping removeClass(String srcName) {
@@ -381,9 +470,22 @@ public void accept(MappingVisitor visitor, VisitOrder order) throws IOException
 				Set<MappingFlag> flags = visitor.getFlags();
 				boolean supplyFieldDstDescs = flags.contains(MappingFlag.NEEDS_DST_FIELD_DESC);
 				boolean supplyMethodDstDescs = flags.contains(MappingFlag.NEEDS_DST_METHOD_DESC);
+				boolean classesFirst = order.isClassesFirst();
+
+				if (classesFirst) {
+					for (ClassEntry cls : order.sortClasses(classesBySrcName.values())) {
+						cls.accept(visitor, order, supplyFieldDstDescs, supplyMethodDstDescs);
+					}
+				}
+
+				for (PackageEntry pkg : order.sortPackages(packagesBySrcName.values())) {
+					pkg.accept(visitor, order);
+				}
 
-				for (ClassEntry cls : order.sortClasses(classesBySrcName.values())) {
-					cls.accept(visitor, order, supplyFieldDstDescs, supplyMethodDstDescs);
+				if (!classesFirst) {
+					for (ClassEntry cls : order.sortClasses(classesBySrcName.values())) {
+						cls.accept(visitor, order, supplyFieldDstDescs, supplyMethodDstDescs);
+					}
 				}
 			}
 		} while (!visitor.visitEnd());
@@ -397,6 +499,7 @@ public void reset() {
 		currentEntry = null;
 		currentClass = null;
 		currentMethod = null;
+		pendingPackages = null;
 		pendingClasses = null;
 		pendingMembers = null;
 	}
@@ -448,8 +551,13 @@ public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) {
 				resizeDstNames(newSize);
 
 				if (indexByDstNames) {
+					packagesByDstNames = Arrays.copyOf(packagesByDstNames, newSize);
 					classesByDstNames = Arrays.copyOf(classesByDstNames, newSize);
 
+					for (int i = newSize - newDstNamespaces; i < packagesByDstNames.length; i++) {
+						packagesByDstNames[i] = new HashMap<String, PackageEntry>(packagesBySrcName.size());
+					}
+
 					for (int i = newSize - newDstNamespaces; i < classesByDstNames.length; i++) {
 						classesByDstNames[i] = new HashMap<>(classesBySrcName.size());
 					}
@@ -469,6 +577,7 @@ public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) {
 			}
 
 			if (indexByDstNames) {
+				initPackagesByDstNames();
 				initClassesByDstNames();
 			}
 		}
@@ -480,6 +589,26 @@ public void visitMetadata(String key, @Nullable String value) {
 		metadata.add(entry);
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) {
+		currentClass = null;
+
+		PackageEntry pkg = (PackageEntry) getPackage(srcName, srcNsMap);
+
+		if (pkg == null) {
+			if (srcNsMap >= 0) { // tree-side srcName unknown
+				pkg = queuePendingPackage(srcName);
+			} else {
+				pkg = new PackageEntry(this, srcName);
+				packagesBySrcName.put(srcName, pkg);
+			}
+		}
+
+		currentEntry = pkg;
+
+		return true;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) {
 		currentMethod = null;
@@ -556,6 +685,21 @@ public boolean visitMethod(String srcName, @Nullable String srcDesc) {
 		return true;
 	}
 
+	private PackageEntry queuePendingPackage(String name) {
+		if (pendingPackages == null) pendingPackages = new HashMap<>();
+		PackageEntry pkg = pendingPackages.get(name);
+
+		if (pkg == null) {
+			pkg = new PackageEntry(this, null);
+			pendingPackages.put(name, pkg);
+		}
+
+		assert srcNsMap >= 0;
+		pkg.setDstNameInternal(name, srcNsMap);
+
+		return pkg;
+	}
+
 	private ClassEntry queuePendingClass(String name) {
 		if (pendingClasses == null) pendingClasses = new HashMap<>();
 		ClassEntry cls = pendingClasses.get(name);
@@ -592,6 +736,21 @@ private MemberEntry<?> queuePendingMember(String name, @Nullable String desc, bo
 		return member;
 	}
 
+	private void addPendingPackage(PackageEntry pkg) {
+		if (pkg.isSrcNameMissing()) {
+			return;
+		}
+
+		String srcName = pkg.getSrcName();
+		PackageEntry existing = packagesBySrcName.get(srcName);
+
+		if (existing == null) {
+			packagesBySrcName.put(srcName, pkg);
+		} else { // copy remaining data
+			existing.copyFrom(pkg, true);
+		}
+	}
+
 	private void addPendingClass(ClassEntry cls) {
 		if (cls.isSrcNameMissing()) {
 			return;
@@ -698,6 +857,15 @@ public boolean visitMethodVar(int lvtRowIndex, int lvIndex, int startOpIdx, int
 	@Override
 	public boolean visitEnd() {
 		// TODO: Don't discard pending elements which are still missing their tree-side src names, upcoming visit passes might provide them
+
+		if (pendingPackages != null) {
+			for (PackageEntry pkg : pendingPackages.values()) {
+				addPendingPackage(pkg);
+			}
+
+			pendingPackages = null;
+		}
+
 		if (pendingClasses != null) {
 			for (ClassEntry cls : pendingClasses.values()) {
 				addPendingClass(cls);
@@ -782,8 +950,8 @@ public void visitDstName(MappedElementKind targetKind, int namespace, String nam
 			if (name.equals(currentEntry.getSrcNameUnchecked())) return;
 
 			switch (currentEntry.getKind()) {
+			case PACKAGE:
 			case CLASS:
-				assert currentClass == currentEntry;
 			case FIELD:
 			case METHOD:
 				if (currentEntry.isSrcNameMissing()) {
@@ -864,6 +1032,11 @@ protected Entry(MemoryMappingTree tree, ElementMapping src, int srcNsEquivalent)
 
 		public abstract MappedElementKind getKind();
 
+		@Override
+		public MappingTree getTree() {
+			return tree;
+		}
+
 		final boolean isSrcNameMissing() {
 			return srcName == null;
 		}
@@ -983,6 +1156,9 @@ protected void copyFrom(T o, boolean replace) {
 			}
 		}
 
+		@Override
+		public abstract String toString();
+
 		private final boolean missingSrcNameAllowed = getKind().level > MappedElementKind.METHOD.level; // args and vars
 		protected final MemoryMappingTree tree;
 		private String srcName;
@@ -990,6 +1166,52 @@ protected void copyFrom(T o, boolean replace) {
 		protected String comment;
 	}
 
+	static final class PackageEntry extends Entry<PackageEntry> implements PackageMapping {
+		PackageEntry(MemoryMappingTree tree, String srcName) {
+			super(tree, srcName);
+		}
+
+		PackageEntry(MemoryMappingTree tree, PackageMapping src, int srcNsEquivalent) {
+			super(tree, src, srcNsEquivalent);
+		}
+
+		@Override
+		public MappedElementKind getKind() {
+			return MappedElementKind.PACKAGE;
+		}
+
+		@Override
+		void setDstNameInternal(String name, int namespace) {
+			if (tree.indexByDstNames) {
+				String oldName = dstNames[namespace];
+
+				if (!Objects.equals(name, oldName)) {
+					Map<String, PackageEntry> map = tree.packagesByDstNames[namespace];
+					if (oldName != null) map.remove(oldName);
+
+					if (name != null) {
+						map.put(name, this);
+					} else {
+						map.remove(oldName);
+					}
+				}
+			}
+
+			super.setDstNameInternal(name, namespace);
+		}
+
+		void accept(MappingVisitor visitor, VisitOrder order) throws IOException {
+			if (visitor.visitPackage(getSrcName())) {
+				acceptElement(visitor, null);
+			}
+		}
+
+		@Override
+		public String toString() {
+			return getSrcNameUnchecked();
+		}
+	}
+
 	static final class ClassEntry extends Entry<ClassEntry> implements ClassMapping {
 		ClassEntry(MemoryMappingTree tree, String srcName) {
 			super(tree, srcName);
@@ -1012,11 +1234,6 @@ public MappedElementKind getKind() {
 			return MappedElementKind.CLASS;
 		}
 
-		@Override
-		public MemoryMappingTree getTree() {
-			return tree;
-		}
-
 		@Override
 		void setDstNameInternal(String name, int namespace) {
 			if (tree.indexByDstNames) {
@@ -1336,11 +1553,6 @@ protected MemberEntry(ClassEntry owner, MemberMapping src, int srcNsEquivalent)
 			this.key = new MemberKey(getSrcName(), srcDesc);
 		}
 
-		@Override
-		public MappingTree getTree() {
-			return owner.tree;
-		}
-
 		@Override
 		public final ClassEntry getOwner() {
 			return owner;
@@ -1776,11 +1988,6 @@ static final class MethodArgEntry extends Entry<MethodArgEntry> implements Metho
 			this.lvIndex = src.getLvIndex();
 		}
 
-		@Override
-		public MappingTree getTree() {
-			return method.owner.tree;
-		}
-
 		@Override
 		public MappedElementKind getKind() {
 			return MappedElementKind.METHOD_ARG;
@@ -1875,11 +2082,6 @@ static final class MethodVarEntry extends Entry<MethodVarEntry> implements Metho
 			this.endOpIdx = src.getEndOpIdx();
 		}
 
-		@Override
-		public MappingTree getTree() {
-			return method.owner.tree;
-		}
-
 		@Override
 		public MappedElementKind getKind() {
 			return MappedElementKind.METHOD_VAR;
@@ -2103,8 +2305,11 @@ public String toString() {
 	private String srcNamespace;
 	private List<String> dstNamespaces = Collections.emptyList();
 	private final List<MetadataEntry> metadata = new ArrayList<>();
+	private final Map<String, PackageEntry> packagesBySrcName = new LinkedHashMap<>();
 	private final Map<String, ClassEntry> classesBySrcName = new LinkedHashMap<>();
+	private final Collection<PackageEntry> packagesView = Collections.unmodifiableCollection(packagesBySrcName.values());
 	private final Collection<ClassEntry> classesView = Collections.unmodifiableCollection(classesBySrcName.values());
+	private Map<String, PackageEntry>[] packagesByDstNames;
 	private Map<String, ClassEntry>[] classesByDstNames;
 
 	private HierarchyInfoProvider<?> hierarchyInfo;
@@ -2115,6 +2320,8 @@ public String toString() {
 	private Entry<?> currentEntry;
 	private ClassEntry currentClass;
 	private MethodEntry currentMethod;
+	/** originalSrcName -> pkgEntry. */
+	private Map<String, PackageEntry> pendingPackages;
 	/** originalSrcName -> clsEntry. */
 	private Map<String, ClassEntry> pendingClasses;
 	private Map<GlobalMemberKey, MemberEntry<?>> pendingMembers;
diff --git a/src/main/java/net/fabricmc/mappingio/tree/VisitOrder.java b/src/main/java/net/fabricmc/mappingio/tree/VisitOrder.java
index fdda2705..389172b8 100644
--- a/src/main/java/net/fabricmc/mappingio/tree/VisitOrder.java
+++ b/src/main/java/net/fabricmc/mappingio/tree/VisitOrder.java
@@ -31,6 +31,7 @@
 import net.fabricmc.mappingio.tree.MappingTreeView.MethodArgMappingView;
 import net.fabricmc.mappingio.tree.MappingTreeView.MethodMappingView;
 import net.fabricmc.mappingio.tree.MappingTreeView.MethodVarMappingView;
+import net.fabricmc.mappingio.tree.MappingTreeView.PackageMappingView;
 
 /**
  * Visitation order configuration for {@link MappingTreeView#accept(net.fabricmc.mappingio.MappingVisitor, VisitOrder)}.
@@ -55,6 +56,7 @@ public static VisitOrder createByInputOrder() {
 	 */
 	public static VisitOrder createByName() {
 		return new VisitOrder()
+				.packagesBySrcName()
 				.classesBySrcName()
 				.fieldsBySrcNameDesc()
 				.methodsBySrcNameDesc()
@@ -64,6 +66,20 @@ public static VisitOrder createByName() {
 
 	// visit order configuration
 
+	public VisitOrder packageComparator(Comparator<PackageMappingView> comparator) {
+		this.packageComparator = comparator;
+
+		return this;
+	}
+
+	public VisitOrder packagesBySrcName() {
+		return packageComparator(compareBySrcName());
+	}
+
+	public VisitOrder packagesBySrcNameShortFirst() {
+		return packageComparator(compareBySrcNameShortFirst());
+	}
+
 	public VisitOrder classComparator(Comparator<ClassMappingView> comparator) {
 		this.classComparator = comparator;
 
@@ -131,6 +147,20 @@ public VisitOrder methodVarsByLvIndex() {
 				.thenComparingInt(MethodVarMappingView::getEndOpIdx));
 	}
 
+	public VisitOrder classesFirst(boolean classesFirst) {
+		this.classesFirst = classesFirst;
+
+		return this;
+	}
+
+	public VisitOrder packagesFirst() {
+		return classesFirst(false);
+	}
+
+	public VisitOrder classesFirst() {
+		return classesFirst(true);
+	}
+
 	public VisitOrder methodsFirst(boolean methodsFirst) {
 		this.methodsFirst = methodsFirst;
 
@@ -277,6 +307,10 @@ public static int compareNullLast(@Nullable String a, @Nullable String b) {
 
 	// application
 
+	public <T extends PackageMappingView> Collection<T> sortPackages(Collection<T> packages) {
+		return sort(packages, packageComparator);
+	}
+
 	public <T extends ClassMappingView> Collection<T> sortClasses(Collection<T> classes) {
 		return sort(classes, classComparator);
 	}
@@ -306,6 +340,10 @@ private static <T> Collection<T> sort(Collection<T> inputs, Comparator<? super T
 		return ret;
 	}
 
+	public boolean isClassesFirst() {
+		return classesFirst;
+	}
+
 	public boolean isMethodsFirst() {
 		return methodsFirst;
 	}
@@ -315,11 +353,13 @@ public boolean isMethodVarsFirst() {
 	}
 
 	private static final AlphanumericComparator ALPHANUM = new AlphanumericComparator(Locale.ROOT);
+	private Comparator<PackageMappingView> packageComparator;
 	private Comparator<ClassMappingView> classComparator;
 	private Comparator<FieldMappingView> fieldComparator;
 	private Comparator<MethodMappingView> methodComparator;
 	private Comparator<MethodArgMappingView> methodArgComparator;
 	private Comparator<MethodVarMappingView> methodVarComparator;
+	private boolean classesFirst;
 	private boolean methodsFirst;
 	private boolean methodVarsFirst;
 }
diff --git a/src/test/java/net/fabricmc/mappingio/test/NameGen.java b/src/test/java/net/fabricmc/mappingio/test/NameGen.java
index bcfa6ac4..d2727c98 100644
--- a/src/test/java/net/fabricmc/mappingio/test/NameGen.java
+++ b/src/test/java/net/fabricmc/mappingio/test/NameGen.java
@@ -26,17 +26,29 @@
 import net.fabricmc.mappingio.MappingVisitor;
 
 class NameGen {
+	boolean visitPackage(MappingVisitor target, int nestLevel, int... dstNs) throws IOException {
+		if (!target.visitPackage(nestLevel <= 0 ? srcOutermostPkgOrCls(pkgKind) : srcInnerPkgOrCls(pkgKind, nestLevel))) {
+			return false;
+		}
+
+		for (int ns : dstNs) {
+			target.visitDstName(pkgKind, ns, nestLevel <= 0 ? dstOutermostPkgOrCls(pkgKind, ns) : dstInnerPkgOrCls(pkgKind, ns));
+		}
+
+		return target.visitElementContent(pkgKind);
+	}
+
 	boolean visitClass(MappingVisitor target, int... dstNs) throws IOException {
 		return visitInnerClass(target, 0, dstNs);
 	}
 
 	boolean visitInnerClass(MappingVisitor target, int nestLevel, int... dstNs) throws IOException {
-		if (!target.visitClass(nestLevel <= 0 ? srcOutermostClass() : srcInnerClasses(nestLevel))) {
+		if (!target.visitClass(nestLevel <= 0 ? srcOutermostPkgOrCls(clsKind) : srcInnerPkgOrCls(clsKind, nestLevel))) {
 			return false;
 		}
 
 		for (int ns : dstNs) {
-			target.visitDstName(clsKind, ns, nestLevel <= 0 ? dstOutermostClass(ns) : dstInnerClasses(ns));
+			target.visitDstName(clsKind, ns, nestLevel <= 0 ? dstOutermostPkgOrCls(clsKind, ns) : dstInnerPkgOrCls(clsKind, ns));
 		}
 
 		return target.visitElementContent(clsKind);
@@ -109,39 +121,45 @@ private String src(MappedElementKind kind) {
 		nsNum = 0;
 		lastKind = kind;
 
-		if (kind == clsKind) {
-			classHasDst = false;
+		if (kind.level == 0) {
+			clsOrPkgHasDst = false;
 		}
 
 		return getPrefix(kind) + "_" + getCounter(kind).incrementAndGet();
 	}
 
-	private String srcOutermostClass() {
-		innerClassNestLevel = 0;
-		String ret = src(clsKind);
+	private String srcOutermostPkgOrCls(MappedElementKind kind) {
+		assert kind.level == 0;
+
+		innerPkgOrClsNestLevel = 0;
+		String ret = src(kind);
+		int counter = getCounter(kind).get();
 
-		if (clsNum.get() % 2 == 0) {
-			ret = "package_" + clsNum.get() + "/" + ret;
+		if (kind == clsKind && counter % 2 == 0) {
+			ret = "package_" + counter + "/" + ret;
 		}
 
 		return ret;
 	}
 
-	private String srcInnerClasses(/* >=1 */ int nestLevel) {
-		if (innerClassNestLevel == 0) {
-			clsNum.decrementAndGet(); // we need the previously generated outer class
+	private String srcInnerPkgOrCls(MappedElementKind kind, /* >=1 */ int nestLevel) {
+		assert kind.level == 0;
+
+		if (innerPkgOrClsNestLevel == 0) {
+			getCounter(kind).decrementAndGet(); // we need the previously generated outer package/class
 		}
 
-		boolean hasDst = classHasDst;
-		StringBuilder sb = new StringBuilder(srcOutermostClass());
+		boolean hasDst = clsOrPkgHasDst;
+		char separator = kind == clsKind ? '$' : '/';
+		StringBuilder sb = new StringBuilder(srcOutermostPkgOrCls(kind));
 
 		for (int i = 0; i < nestLevel; i++) {
-			sb.append('$');
-			sb.append(src(clsKind));
+			sb.append(separator);
+			sb.append(src(kind));
 		}
 
-		classHasDst = hasDst;
-		innerClassNestLevel = nestLevel;
+		clsOrPkgHasDst = hasDst;
+		innerPkgOrClsNestLevel = nestLevel;
 		return sb.toString();
 	}
 
@@ -154,51 +172,59 @@ private String dst(MappedElementKind kind, int ns) {
 			nsNum = ns + 1;
 		}
 
-		if (kind == clsKind) {
-			classHasDst = true;
+		if (kind.level == 0) {
+			clsOrPkgHasDst = true;
 		}
 
 		return getPrefix(kind) + getCounter(kind).get() + "Ns" + ns + "Rename";
 	}
 
-	private String dstOutermostClass(int ns) {
-		String ret = dst(clsKind, ns);
+	private String dstOutermostPkgOrCls(MappedElementKind kind, int ns) {
+		assert kind.level == 0;
+
+		String ret = dst(kind, ns);
+		AtomicInteger counter = getCounter(kind);
 
-		if (clsNum.get() % 3 == 0) {
-			int num = clsNum.get() % 6 == 0 && innerClassNestLevel == 0
-					? clsNum.get() + 1
-					: clsNum.get();
-			ret = "package_" + num + "/" + ret;
+		if (counter.get() % 3 == 0) {
+			int num = counter.get() % 6 == 0
+					? counter.get() + 1
+					: counter.get();
+			String pkgName = kind == pkgKind ? "filler_" : "package_";
+			ret = pkgName + num + "/" + ret;
 		}
 
 		return ret;
 	}
 
-	private String dstInnerClasses(int ns) {
-		boolean hasDst = classHasDst;
-		int nestLevel = innerClassNestLevel;
-		StringBuilder sb = new StringBuilder(dst(clsKind, ns));
+	private String dstInnerPkgOrCls(MappedElementKind kind, int ns) {
+		assert kind.level == 0;
+
+		boolean hasDst = clsOrPkgHasDst;
+		int nestLevel = innerPkgOrClsNestLevel;
+		char separator = kind == clsKind ? '$' : '/';
+		AtomicInteger counter = getCounter(kind);
+		StringBuilder sb = new StringBuilder(dst(kind, ns));
 
 		for (int i = nestLevel - 1; i >= 0; i--) {
-			sb.insert(0, '$');
-			clsNum.decrementAndGet();
+			sb.insert(0, separator);
+			counter.decrementAndGet();
 
 			if (!hasDst) {
-				clsNum.decrementAndGet();
+				counter.decrementAndGet();
 			}
 
 			sb.insert(0, hasDst
 					? i == 0
-							? dstOutermostClass(ns)
-							: dst(clsKind, ns)
+							? dstOutermostPkgOrCls(kind, ns)
+							: dst(kind, ns)
 					: i == 0
-							? srcOutermostClass()
-							: src(clsKind));
+							? srcOutermostPkgOrCls(kind)
+							: src(kind));
 		}
 
-		classHasDst = hasDst;
-		innerClassNestLevel = nestLevel;
-		clsNum.addAndGet(nestLevel);
+		clsOrPkgHasDst = hasDst;
+		innerPkgOrClsNestLevel = nestLevel;
+		counter.addAndGet(nestLevel);
 		return sb.toString();
 	}
 
@@ -215,6 +241,8 @@ private String desc(MappedElementKind kind) {
 
 	private AtomicInteger getCounter(MappedElementKind kind) {
 		switch (kind) {
+		case PACKAGE:
+			return pkgNum;
 		case CLASS:
 			return clsNum;
 		case FIELD:
@@ -232,6 +260,8 @@ private AtomicInteger getCounter(MappedElementKind kind) {
 
 	private String getPrefix(MappedElementKind kind) {
 		switch (kind) {
+		case PACKAGE:
+			return pkgPrefix;
 		case CLASS:
 			return clsPrefix;
 		case FIELD:
@@ -247,6 +277,7 @@ private String getPrefix(MappedElementKind kind) {
 		}
 	}
 
+	private static final String pkgPrefix = "package";
 	private static final String clsPrefix = "class";
 	private static final String fldPrefix = "field";
 	private static final String mthPrefix = "method";
@@ -255,11 +286,13 @@ private String getPrefix(MappedElementKind kind) {
 	private static final String comment = "This is a comment";
 	private static final List<String> fldDescs = Collections.unmodifiableList(Arrays.asList("I", "Lcls;", "Lpkg/cls;", "[I", null));
 	private static final List<String> mthDescs = Collections.unmodifiableList(Arrays.asList("()I", "(I)V", "(Lcls;)Lcls;", "(ILcls;)Lpkg/cls;", "(Lcls;[I)[[B", null));
+	private static final MappedElementKind pkgKind = MappedElementKind.PACKAGE;
 	private static final MappedElementKind clsKind = MappedElementKind.CLASS;
 	private static final MappedElementKind fldKind = MappedElementKind.FIELD;
 	private static final MappedElementKind mthKind = MappedElementKind.METHOD;
 	private static final MappedElementKind argKind = MappedElementKind.METHOD_ARG;
 	private static final MappedElementKind varKind = MappedElementKind.METHOD_VAR;
+	private final AtomicInteger pkgNum = new AtomicInteger();
 	private final AtomicInteger clsNum = new AtomicInteger();
 	private final AtomicInteger fldNum = new AtomicInteger();
 	private final AtomicInteger mthNum = new AtomicInteger();
@@ -268,6 +301,6 @@ private String getPrefix(MappedElementKind kind) {
 	private int nsNum;
 	private int counter;
 	private MappedElementKind lastKind;
-	private boolean classHasDst;
-	private int innerClassNestLevel;
+	private boolean clsOrPkgHasDst;
+	private int innerPkgOrClsNestLevel;
 }
diff --git a/src/test/java/net/fabricmc/mappingio/test/TestMappings.java b/src/test/java/net/fabricmc/mappingio/test/TestMappings.java
index 6060e9d3..c7303d9a 100644
--- a/src/test/java/net/fabricmc/mappingio/test/TestMappings.java
+++ b/src/test/java/net/fabricmc/mappingio/test/TestMappings.java
@@ -64,6 +64,14 @@ public static <T extends MappingVisitor> T generateValid(T target) throws IOExce
 			int[] dstNs = new int[] { 0, 1 };
 			NameGen nameGen = new NameGen();
 
+			if (nameGen.visitPackage(delegate, 0, dstNs)) {
+				nameGen.visitComment(delegate);
+			}
+
+			if (nameGen.visitPackage(delegate, 1, dstNs)) {
+				nameGen.visitComment(delegate);
+			}
+
 			if (nameGen.visitClass(delegate, dstNs)) {
 				nameGen.visitField(delegate, dstNs);
 
@@ -97,6 +105,13 @@ public void visitMetadata(String key, @Nullable String value) throws IOException
 				super.visitMetadata(key, key.equals("name") ? "repeated-elements" : value);
 			}
 
+			@Override
+			public boolean visitPackage(String srcName) throws IOException {
+				replayQueue.clear();
+				replayQueue.add(Unchecked.runnable(() -> super.visitPackage(srcName)));
+				return super.visitPackage(srcName);
+			}
+
 			@Override
 			public boolean visitClass(String srcName) throws IOException {
 				replayQueue.clear();
@@ -188,6 +203,20 @@ public static <T extends MappingVisitor> T generateHoles(T target) throws IOExce
 		if (delegate.visitContent()) {
 			NameGen nameGen = new NameGen();
 
+			// Packages
+			nameGen.visitPackage(delegate, 0, 0);
+			nameGen.visitPackage(delegate, 0, 0);
+			nameGen.visitPackage(delegate, 0, 0);
+
+			nameGen.visitPackage(delegate, 0, 1);
+			nameGen.visitPackage(delegate, 0, 1);
+			nameGen.visitPackage(delegate, 0, 1);
+
+			nameGen.visitPackage(delegate, 1, 0);
+			nameGen.visitPackage(delegate, 1, 0);
+			nameGen.visitPackage(delegate, 1, 0);
+			nameGen.visitPackage(delegate, 1, 0);
+
 			// (Inner) Classes
 			for (int nestLevel = 0; nestLevel <= 2; nestLevel++) {
 				nameGen.visitClass(delegate);
@@ -464,5 +493,10 @@ public boolean supportsGeneration() {
 		}
 
 		public abstract <T extends MappingVisitor> T generate(T target) throws IOException;
+
+		@Override
+		public String toString() {
+			return TestUtil.getResource("/").relativize(path).toString();
+		}
 	}
 }
diff --git a/src/test/java/net/fabricmc/mappingio/test/tests/reading/DetectionTest.java b/src/test/java/net/fabricmc/mappingio/test/tests/reading/DetectionTest.java
index 000cb2cb..7033937c 100644
--- a/src/test/java/net/fabricmc/mappingio/test/tests/reading/DetectionTest.java
+++ b/src/test/java/net/fabricmc/mappingio/test/tests/reading/DetectionTest.java
@@ -16,6 +16,7 @@
 
 package net.fabricmc.mappingio.test.tests.reading;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -43,7 +44,7 @@ public void run() throws Exception {
 				if (format == MappingFormat.RECAF_SIMPLE_FILE) {
 					assertThrows(AssertionFailedError.class, () -> check(dir, format));
 				} else {
-					check(dir, format);
+					assertDoesNotThrow(() -> check(dir, format), "Failed for " + dir + " with " + format);
 				}
 			}
 		}
diff --git a/src/test/java/net/fabricmc/mappingio/test/tests/reading/ValidContentReadTest.java b/src/test/java/net/fabricmc/mappingio/test/tests/reading/ValidContentReadTest.java
index 10eac065..93965d75 100644
--- a/src/test/java/net/fabricmc/mappingio/test/tests/reading/ValidContentReadTest.java
+++ b/src/test/java/net/fabricmc/mappingio/test/tests/reading/ValidContentReadTest.java
@@ -16,6 +16,8 @@
 
 package net.fabricmc.mappingio.test.tests.reading;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
 import java.nio.file.Files;
 
 import org.jetbrains.annotations.Nullable;
@@ -39,7 +41,7 @@ public class ValidContentReadTest {
 	public void run() throws Exception {
 		for (MappingDir dir : TestMappings.values()) {
 			for (MappingFormat format : MappingFormat.values()) {
-				check(dir, format);
+				assertDoesNotThrow(() -> check(dir, format), "Failed for " + dir + " with " + format);
 			}
 		}
 	}
diff --git a/src/test/java/net/fabricmc/mappingio/test/tests/visiting/VisitEndTest.java b/src/test/java/net/fabricmc/mappingio/test/tests/visiting/VisitEndTest.java
index 253af226..05e64cc6 100644
--- a/src/test/java/net/fabricmc/mappingio/test/tests/visiting/VisitEndTest.java
+++ b/src/test/java/net/fabricmc/mappingio/test/tests/visiting/VisitEndTest.java
@@ -16,6 +16,7 @@
 
 package net.fabricmc.mappingio.test.tests.visiting;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -46,7 +47,7 @@ public class VisitEndTest {
 	public void run() throws Exception {
 		for (MappingDir dir : TestMappings.values()) {
 			for (MappingFormat format : MappingFormat.values()) {
-				check(dir, format);
+				assertDoesNotThrow(() -> check(dir, format), "Failed for " + dir + " with " + format);
 			}
 		}
 	}
@@ -129,6 +130,13 @@ public boolean visitContent() throws IOException {
 			return true;
 		}
 
+		@Override
+		public boolean visitPackage(String srcName) throws IOException {
+			check();
+			tree.visitPackage(srcName);
+			return true;
+		}
+
 		@Override
 		public boolean visitClass(String srcName) throws IOException {
 			check();
diff --git a/src/test/java/net/fabricmc/mappingio/test/tests/writing/WriteTest.java b/src/test/java/net/fabricmc/mappingio/test/tests/writing/WriteTest.java
index 6fd5a540..1f03baef 100644
--- a/src/test/java/net/fabricmc/mappingio/test/tests/writing/WriteTest.java
+++ b/src/test/java/net/fabricmc/mappingio/test/tests/writing/WriteTest.java
@@ -16,6 +16,8 @@
 
 package net.fabricmc.mappingio.test.tests.writing;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
 import java.io.IOException;
 import java.nio.file.Path;
 
@@ -48,7 +50,7 @@ public class WriteTest {
 	public void run() throws Exception {
 		for (MappingDir dir : TestMappings.values()) {
 			for (MappingFormat format : MappingFormat.values()) {
-				check(dir, format);
+				assertDoesNotThrow(() -> check(dir, format), "Failed for " + dir + " with " + format);
 			}
 		}
 	}
diff --git a/src/test/java/net/fabricmc/mappingio/test/visitors/NopMappingVisitor.java b/src/test/java/net/fabricmc/mappingio/test/visitors/NopMappingVisitor.java
index e2206f56..60e72c43 100644
--- a/src/test/java/net/fabricmc/mappingio/test/visitors/NopMappingVisitor.java
+++ b/src/test/java/net/fabricmc/mappingio/test/visitors/NopMappingVisitor.java
@@ -43,6 +43,11 @@ public boolean visitContent() throws IOException {
 		return visitSubVisitors;
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		return visitSubVisitors;
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		return visitSubVisitors;
diff --git a/src/test/java/net/fabricmc/mappingio/test/visitors/SubsetAssertingVisitor.java b/src/test/java/net/fabricmc/mappingio/test/visitors/SubsetAssertingVisitor.java
index e256e6fc..c76a15df 100644
--- a/src/test/java/net/fabricmc/mappingio/test/visitors/SubsetAssertingVisitor.java
+++ b/src/test/java/net/fabricmc/mappingio/test/visitors/SubsetAssertingVisitor.java
@@ -41,6 +41,7 @@
 import net.fabricmc.mappingio.tree.MappingTreeView.MethodArgMappingView;
 import net.fabricmc.mappingio.tree.MappingTreeView.MethodMappingView;
 import net.fabricmc.mappingio.tree.MappingTreeView.MethodVarMappingView;
+import net.fabricmc.mappingio.tree.MappingTreeView.PackageMappingView;
 
 /**
  * A visitor which asserts that the visited mappings are a subset of a superset tree.
@@ -53,6 +54,7 @@ public class SubsetAssertingVisitor implements FlatMappingVisitor {
 	 */
 	public SubsetAssertingVisitor(MappingTreeView supTree, @Nullable MappingFormat supFormat, @Nullable MappingFormat subFormat) {
 		this.supTree = supTree;
+		this.supFormat = supFormat;
 		this.subFormat = subFormat;
 		this.supDstNsCount = supTree.getMaxNamespaceId();
 		this.supFeatures = supFormat == null ? FeatureSetInstantiator.withFullSupport() : supFormat.features();
@@ -103,9 +105,89 @@ public void visitNamespaces(String srcNamespace, List<String> dstNamespaces) thr
 		}
 	}
 
+	@Override
+	public boolean visitPackage(String srcName, @Nullable String[] dstNames) throws IOException {
+		if (!supFeatures.supportsPackages()) return false;
+
+		PackageMappingView supPkg = supTree.getPackage(srcName);
+		boolean supHasDstNames = supFeatures.packages().dstNames() != FeaturePresence.ABSENT;
+		boolean subHasDstNames = subFeatures.packages().dstNames() != FeaturePresence.ABSENT;
+		boolean supHasStructureModification = supFeatures.packages().hasStructureModification();
+
+		if (supPkg == null) { // supTree doesn't have this package, ensure the incoming mappings don't have any data for it
+			if (supHasDstNames && subHasDstNames) {
+				String[] subDstNames = supFeatures.hasNamespaces() || dstNames == null ? dstNames : new String[]{dstNames[subNsIfSupNotNamespaced]};
+
+				if (!isEmpty(subDstNames)) {
+					boolean error = true;
+
+					if (!supHasStructureModification) {
+						int srcNameSlashCount = countOccurrences(srcName, '/');
+
+						for (String subDstName : subDstNames) {
+							if (subDstName != null) {
+								if (countOccurrences(subDstName, '/') == srcNameSlashCount) {
+									error = true;
+									break;
+								} else {
+									// The incoming package has been moved, which supFormat doesn't support, that's why it's missing from supTree
+									error = false;
+								}
+							}
+						}
+					}
+
+					if (error) {
+						throw new AssertionError("Incoming package not contained in supTree: " + srcName);
+					}
+				}
+			}
+
+			return true; // ensure there is no element content
+		}
+
+		Map<String, String> supDstNamesByNsName = new HashMap<>();
+
+		for (int supNs = 0; supNs < supDstNsCount; supNs++) {
+			supDstNamesByNsName.put(supTree.getNamespaceName(supNs), supPkg.getDstName(supNs));
+		}
+
+		if (supHasDstNames && subHasDstNames && dstNames != null) {
+			for (int subNs = 0; subNs < subDstNamespaces.size(); subNs++) {
+				String supDstName = supDstNamesByNsName.get(subDstNamespaces.get(subNs));
+				if (supDstName == null && !supFeatures.hasNamespaces()) continue;
+
+				String subDstName = dstNames[subNs];
+				if (subDstName == null && (supDstName == null || Objects.equals(supDstName, srcName))) continue; // uncompleted dst name
+
+				assertEquals(supDstName != null ? supDstName : srcName, subDstName, "Incoming package destination name differs from supTree");
+			}
+		}
+
+		return true;
+	}
+
+	@Override
+	public void visitPackageComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException {
+		assert supFeatures.supportsPackages();
+
+		if (supFeatures.elementComments() == ElementCommentSupport.NONE) {
+			return;
+		}
+
+		PackageMappingView supPkg = Objects.requireNonNull(supTree.getPackage(srcName), "Incoming package comment's parent package not contained in supTree: " + srcName);
+
+		assertEquals(supPkg.getComment(), comment, "Incoming package comment not contained in supTree: " + srcName);
+	}
+
 	@Override
 	public boolean visitClass(String srcName, @Nullable String[] dstNames) throws IOException {
-		if (!supFeatures.supportsClasses()) return true; // sub-elements might still be supported
+		if (!supFeatures.supportsClasses()) {
+			return supFeatures.supportsFields()
+					|| supFeatures.supportsMethods()
+					|| supFeatures.supportsArgs()
+					|| supFeatures.supportsVars();
+		}
 
 		ClassMappingView supCls = supTree.getClass(srcName);
 		boolean supHasDstNames = supFeatures.classes().dstNames() != FeaturePresence.ABSENT;
@@ -143,7 +225,7 @@ public boolean visitClass(String srcName, @Nullable String[] dstNames) throws IO
 				}
 			}
 
-			return true;
+			return true; // ensure there is no element content
 		}
 
 		Map<String, String> supDstNamesByNsName = new HashMap<>();
@@ -187,7 +269,9 @@ public boolean visitClass(String srcName, @Nullable String[] dstNames) throws IO
 
 	@Override
 	public void visitClassComment(String srcName, @Nullable String[] dstNames, String comment) throws IOException {
-		if (!supFeatures.supportsClasses() || supFeatures.elementComments() == ElementCommentSupport.NONE) return;
+		if (!supFeatures.supportsClasses() || supFeatures.elementComments() == ElementCommentSupport.NONE) {
+			return;
+		}
 
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcName), "Incoming class comment's parent class not contained in supTree: " + srcName);
 
@@ -197,7 +281,7 @@ public void visitClassComment(String srcName, @Nullable String[] dstNames, Strin
 	@Override
 	public boolean visitField(String srcClsName, String srcName, @Nullable String srcDesc,
 			@Nullable String[] dstClsNames, @Nullable String[] dstNames, @Nullable String[] dstDescs) throws IOException {
-		if (!supFeatures.supportsFields()) return true;
+		if (!supFeatures.supportsFields()) return false;
 
 		String subFldId = srcClsName + "#" + srcName + ":" + srcDesc;
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcClsName), "Incoming field's parent class not contained in supTree: " + subFldId);
@@ -222,7 +306,7 @@ public boolean visitField(String srcClsName, String srcName, @Nullable String sr
 			boolean missingRequiredSrcDesc = supRequiresSrcDescs && srcDesc == null;
 
 			assertTrue(noData || missingRequiredSrcDesc, "Incoming field not contained in supTree: " + subFldId);
-			return !missingRequiredSrcDesc;
+			return !missingRequiredSrcDesc; // ensure there is no element content
 		}
 
 		String supFldId = srcClsName + "#" + srcName + ":" + supFld.getSrcDesc();
@@ -269,7 +353,11 @@ public boolean visitField(String srcClsName, String srcName, @Nullable String sr
 	@Override
 	public void visitFieldComment(String srcClsName, String srcName, @Nullable String srcDesc,
 			@Nullable String[] dstClsNames, @Nullable String[] dstNames, @Nullable String[] dstDescs, String comment) throws IOException {
-		if (!supFeatures.supportsFields() || supFeatures.elementComments() == ElementCommentSupport.NONE) return;
+		assert supFeatures.supportsFields();
+
+		if (supFeatures.elementComments() == ElementCommentSupport.NONE) {
+			return;
+		}
 
 		String subFldId = srcClsName + "#" + srcName + ":" + srcDesc;
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcClsName), "Incoming field comment's parent class not contained in supTree: " + subFldId);
@@ -281,7 +369,9 @@ public void visitFieldComment(String srcClsName, String srcName, @Nullable Strin
 	@Override
 	public boolean visitMethod(String srcClsName, String srcName, @Nullable String srcDesc,
 			@Nullable String[] dstClsNames, @Nullable String[] dstNames, @Nullable String[] dstDescs) throws IOException {
-		if (!supFeatures.supportsMethods()) return true;
+		if (!supFeatures.supportsMethods()) {
+			return supFeatures.supportsArgs() || supFeatures.supportsVars();
+		}
 
 		String subMthId = srcClsName + "#" + srcName + srcDesc;
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcClsName), "Incoming method's parent class not contained in supTree: " + subMthId);
@@ -306,7 +396,7 @@ public boolean visitMethod(String srcClsName, String srcName, @Nullable String s
 			boolean missingRequiredSrcDesc = supRequiresSrcDescs && srcDesc == null;
 
 			assertTrue(noData || missingRequiredSrcDesc, "Incoming method not contained in supTree: " + subMthId);
-			return !missingRequiredSrcDesc;
+			return !missingRequiredSrcDesc; // ensure there is no element content
 		}
 
 		String supMthId = srcClsName + "#" + srcName + supMth.getSrcDesc();
@@ -354,7 +444,9 @@ public boolean visitMethod(String srcClsName, String srcName, @Nullable String s
 	@Override
 	public void visitMethodComment(String srcClsName, String srcName, @Nullable String srcDesc,
 			@Nullable String[] dstClsNames, @Nullable String[] dstNames, @Nullable String[] dstDescs, String comment) throws IOException {
-		if (!supFeatures.supportsMethods() || supFeatures.elementComments() == ElementCommentSupport.NONE) return;
+		if (!supFeatures.supportsMethods() || supFeatures.elementComments() == ElementCommentSupport.NONE) {
+			return;
+		}
 
 		String subMthId = srcClsName + "#" + srcName + srcDesc;
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcClsName), "Incoming method comment's parent class not contained in supTree: " + subMthId);
@@ -366,7 +458,7 @@ public void visitMethodComment(String srcClsName, String srcName, @Nullable Stri
 	@Override
 	public boolean visitMethodArg(String srcClsName, String srcMethodName, @Nullable String srcMethodDesc, int argPosition, int lvIndex, @Nullable String srcName,
 			@Nullable String[] dstClsNames, @Nullable String[] dstMethodNames, @Nullable String[] dstMethodDescs, @Nullable String[] dstNames) throws IOException {
-		if (!supFeatures.supportsArgs()) return true;
+		if (!supFeatures.supportsArgs()) return false;
 
 		String subArgId = srcClsName + "#" + srcMethodName + srcMethodDesc + ":" + argPosition + ":" + lvIndex + ":" + srcName;
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcClsName), "Incoming arg's parent class not contained in supTree: " + subArgId);
@@ -389,7 +481,7 @@ public boolean visitMethodArg(String srcClsName, String srcMethodName, @Nullable
 				assertTrue(isEmpty(subDstNames), "Incoming arg not contained in supTree: " + subArgId);
 			}
 
-			return true;
+			return true; // ensure there is no element content
 		}
 
 		Map<String, String> supDstNamesByNsName = new HashMap<>();
@@ -428,7 +520,11 @@ public boolean visitMethodArg(String srcClsName, String srcMethodName, @Nullable
 	@Override
 	public void visitMethodArgComment(String srcClsName, String srcMethodName, @Nullable String srcMethodDesc, int argPosition, int lvIndex, @Nullable String srcArgName,
 			@Nullable String[] dstClsNames, @Nullable String[] dstMethodNames, @Nullable String[] dstMethodDescs, @Nullable String[] dstNames, String comment) throws IOException {
-		if (!supFeatures.supportsArgs() || supFeatures.elementComments() == ElementCommentSupport.NONE) return;
+		assert supFeatures.supportsArgs();
+
+		if (supFeatures.elementComments() == ElementCommentSupport.NONE) {
+			return;
+		}
 
 		String subArgId = srcClsName + "#" + srcMethodName + srcMethodDesc + ":" + argPosition + ":" + lvIndex + ":" + srcArgName;
 
@@ -442,7 +538,7 @@ public void visitMethodArgComment(String srcClsName, String srcMethodName, @Null
 	@Override
 	public boolean visitMethodVar(String srcClsName, String srcMethodName, @Nullable String srcMethodDesc, int lvtRowIndex, int lvIndex, int startOpIdx, int endOpIdx, @Nullable String srcName,
 			@Nullable String[] dstClsNames, @Nullable String[] dstMethodNames, @Nullable String[] dstMethodDescs, @Nullable String[] dstNames) throws IOException {
-		if (!supFeatures.supportsVars()) return true;
+		if (!supFeatures.supportsVars()) return false;
 
 		String subVarId = srcClsName + "#" + srcMethodName + srcMethodDesc + ":" + lvtRowIndex + ":" + lvIndex + ":" + startOpIdx + ":" + endOpIdx + ":" + srcName;
 		ClassMappingView supCls = Objects.requireNonNull(supTree.getClass(srcClsName), "Incoming var's parent class not contained in supTree: " + subVarId);
@@ -469,7 +565,7 @@ public boolean visitMethodVar(String srcClsName, String srcMethodName, @Nullable
 				assertTrue(isEmpty(subDstNames), "Incoming var not contained in supTree: " + subVarId);
 			}
 
-			return true;
+			return true; // ensure there is no element content
 		}
 
 		Map<String, String> supDstNamesByNsName = new HashMap<>();
@@ -516,7 +612,11 @@ public boolean visitMethodVar(String srcClsName, String srcMethodName, @Nullable
 	@Override
 	public void visitMethodVarComment(String srcClsName, String srcMethodName, @Nullable String srcMethodDesc, int lvtRowIndex, int lvIndex, int startOpIdx, int endOpIdx, @Nullable String srcVarName,
 			@Nullable String[] dstClsNames, @Nullable String[] dstMethodNames, @Nullable String[] dstMethodDescs, @Nullable String[] dstNames, String comment) throws IOException {
-		if (!supFeatures.supportsVars() || supFeatures.elementComments() == ElementCommentSupport.NONE) return;
+		assert supFeatures.supportsVars();
+
+		if (supFeatures.elementComments() == ElementCommentSupport.NONE) {
+			return;
+		}
 
 		String subVarId = srcClsName + "#" + srcMethodName + srcMethodDesc + ":" + lvtRowIndex + ":" + lvIndex + ":" + startOpIdx + ":" + endOpIdx + ":" + srcVarName;
 
@@ -537,6 +637,16 @@ private boolean isEmpty(String[] arr) {
 		return true;
 	}
 
+	private int countOccurrences(String str, char c) {
+		int count = 0;
+
+		for (int i = 0; i < str.length(); i++) {
+			if (str.charAt(i) == c) count++;
+		}
+
+		return count;
+	}
+
 	@Nullable
 	private String getPackage(String name) {
 		int lastSlash = name.lastIndexOf('/');
@@ -545,6 +655,7 @@ private String getPackage(String name) {
 
 	private final MappingTreeView supTree;
 	private final int supDstNsCount;
+	private final MappingFormat supFormat;
 	private final MappingFormat subFormat;
 	private final FeatureSet supFeatures;
 	private final FeatureSet subFeatures;
diff --git a/src/test/java/net/fabricmc/mappingio/test/visitors/VisitOrderVerifyingVisitor.java b/src/test/java/net/fabricmc/mappingio/test/visitors/VisitOrderVerifyingVisitor.java
index 905d6f9f..7276a92a 100644
--- a/src/test/java/net/fabricmc/mappingio/test/visitors/VisitOrderVerifyingVisitor.java
+++ b/src/test/java/net/fabricmc/mappingio/test/visitors/VisitOrderVerifyingVisitor.java
@@ -48,6 +48,7 @@ private void init() {
 		visitedNamespaces = false;
 		visitedMetadata = false;
 		visitedContent = false;
+		visitedPackage = false;
 		visitedClass = false;
 		visitedField = false;
 		visitedMethod = false;
@@ -103,6 +104,7 @@ public void visitMetadata(String key, @Nullable String value) throws IOException
 		assertNamespacesVisited();
 
 		visitedMetadata = true;
+		visitedPackage = false;
 		visitedClass = false;
 		visitedField = false;
 		visitedMethod = false;
@@ -120,6 +122,29 @@ public boolean visitContent() throws IOException {
 		return super.visitContent();
 	}
 
+	@Override
+	public boolean visitPackage(String srcName) throws IOException {
+		MappedElementKind elementKind = MappedElementKind.PACKAGE;
+		SrcInfo srcInfo = new SrcInfo().srcName(srcName);
+
+		assertContentVisited();
+		assertLastElementContentVisited();
+		resetLastSrcInfoDownTo(elementKind.level);
+		assertNewSrcInfo(elementKind, srcInfo);
+
+		visitedPackage = true;
+		visitedClass = false;
+		visitedField = false;
+		visitedMethod = false;
+		visitedMethodArg = false;
+		visitedMethodVar = false;
+		lastVisitedElement = elementKind;
+		lastSrcInfo.put(elementKind, srcInfo);
+		resetVisitedElementContentDownTo(elementKind.level);
+
+		return visitedLastElement = super.visitPackage(srcName);
+	}
+
 	@Override
 	public boolean visitClass(String srcName) throws IOException {
 		MappedElementKind elementKind = MappedElementKind.CLASS;
@@ -130,6 +155,7 @@ public boolean visitClass(String srcName) throws IOException {
 		resetLastSrcInfoDownTo(elementKind.level);
 		assertNewSrcInfo(elementKind, srcInfo);
 
+		visitedPackage = false;
 		visitedClass = true;
 		visitedField = false;
 		visitedMethod = false;
@@ -450,6 +476,7 @@ private void assertNewSrcInfo(MappedElementKind kind, SrcInfo srcInfo) {
 	private boolean visitedNamespaces;
 	private boolean visitedMetadata;
 	private boolean visitedContent;
+	private boolean visitedPackage;
 	private boolean visitedClass;
 	private boolean visitedField;
 	private boolean visitedMethod;
diff --git a/src/test/resources/reading/holes/csrg.csrg b/src/test/resources/reading/holes/csrg.csrg
index 0568f73a..e7815365 100644
--- a/src/test/resources/reading/holes/csrg.csrg
+++ b/src/test/resources/reading/holes/csrg.csrg
@@ -1,3 +1,10 @@
+package_1/ package1Ns0Rename/
+package_2/ package2Ns0Rename/
+package_3/ filler_3/package3Ns0Rename/
+package_6/package_7/ filler_7/package6Ns0Rename/package7Ns0Rename/
+package_8/package_9/ package8Ns0Rename/package9Ns0Rename/
+package_10/package_11/ package10Ns0Rename/package11Ns0Rename/
+package_12/package_13/ filler_13/package12Ns0Rename/package13Ns0Rename/
 class_3 package_3/class3Ns0Rename
 package_6/class_6 package_7/class6Ns0Rename
 class_9$class_10 class_9$class10Ns0Rename
diff --git a/src/test/resources/reading/holes/jobf.jobf b/src/test/resources/reading/holes/jobf.jobf
index b5e6978b..24d52d2c 100644
--- a/src/test/resources/reading/holes/jobf.jobf
+++ b/src/test/resources/reading/holes/jobf.jobf
@@ -1,3 +1,7 @@
+p package_1 = package1Ns0Rename
+p package_2 = package2Ns0Rename
+p package_8.package_9 = package8Ns0Rename.package9Ns0Rename
+p package_10.package_11 = package10Ns0Rename.package11Ns0Rename
 c class_9$class_10 = class_9$class10Ns0Rename
 c class_15$class_16 = class_15$class16Ns0Rename
 c package_20.class_20$class_21$class_22 = class_20$class_21$class22Ns0Rename
diff --git a/src/test/resources/reading/holes/migration-map.xml b/src/test/resources/reading/holes/migration-map.xml
index 849e7717..61cf008a 100644
--- a/src/test/resources/reading/holes/migration-map.xml
+++ b/src/test/resources/reading/holes/migration-map.xml
@@ -1,5 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <migrationMap>
+	<entry oldName="package_1" newName="package1Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_2" newName="package2Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_3" newName="filler_3.package3Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_6.package_7" newName="filler_7.package6Ns0Rename.package7Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_8.package_9" newName="package8Ns0Rename.package9Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_10.package_11" newName="package10Ns0Rename.package11Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_12.package_13" newName="filler_13.package12Ns0Rename.package13Ns0Rename" type="package" recursive="false"/>
 	<entry oldName="class_3" newName="package_3.class3Ns0Rename" type="class"/>
 	<entry oldName="package_6.class_6" newName="package_7.class6Ns0Rename" type="class"/>
 	<entry oldName="class_9$class_10" newName="class_9$class10Ns0Rename" type="class"/>
diff --git a/src/test/resources/reading/holes/srg.srg b/src/test/resources/reading/holes/srg.srg
index 348b2d7b..02bf2613 100644
--- a/src/test/resources/reading/holes/srg.srg
+++ b/src/test/resources/reading/holes/srg.srg
@@ -1,3 +1,10 @@
+PK: package_1/ package1Ns0Rename/
+PK: package_2/ package2Ns0Rename/
+PK: package_3/ filler_3/package3Ns0Rename/
+PK: package_6/package_7/ filler_7/package6Ns0Rename/package7Ns0Rename/
+PK: package_8/package_9/ package8Ns0Rename/package9Ns0Rename/
+PK: package_10/package_11/ package10Ns0Rename/package11Ns0Rename/
+PK: package_12/package_13/ filler_13/package12Ns0Rename/package13Ns0Rename/
 CL: class_3 package_3/class3Ns0Rename
 CL: package_6/class_6 package_7/class6Ns0Rename
 CL: class_9$class_10 class_9$class10Ns0Rename
diff --git a/src/test/resources/reading/holes/tsrg.tsrg b/src/test/resources/reading/holes/tsrg.tsrg
index d41d5af1..ff9cb2e6 100644
--- a/src/test/resources/reading/holes/tsrg.tsrg
+++ b/src/test/resources/reading/holes/tsrg.tsrg
@@ -1,3 +1,10 @@
+package_1/ package1Ns0Rename/
+package_2/ package2Ns0Rename/
+package_3/ filler_3/package3Ns0Rename/
+package_6/package_7/ filler_7/package6Ns0Rename/package7Ns0Rename/
+package_8/package_9/ package8Ns0Rename/package9Ns0Rename/
+package_10/package_11/ package10Ns0Rename/package11Ns0Rename/
+package_12/package_13/ filler_13/package12Ns0Rename/package13Ns0Rename/
 class_3 package_3/class3Ns0Rename
 package_6/class_6 package_7/class6Ns0Rename
 class_9$class_10 class_9$class10Ns0Rename
diff --git a/src/test/resources/reading/holes/tsrgV2.tsrg b/src/test/resources/reading/holes/tsrgV2.tsrg
index 1dbfb6e1..5c7e58fe 100644
--- a/src/test/resources/reading/holes/tsrgV2.tsrg
+++ b/src/test/resources/reading/holes/tsrgV2.tsrg
@@ -1,4 +1,14 @@
 tsrg2 source target target2
+package_1/ package1Ns0Rename/ package_1/
+package_2/ package2Ns0Rename/ package_2/
+package_3/ filler_3/package3Ns0Rename/ package_3/
+package_4/ package_4/ package4Ns1Rename/
+package_5/ package_5/ package5Ns1Rename/
+package_6/ package_6/ filler_7/package6Ns1Rename/
+package_6/package_7/ filler_7/package6Ns0Rename/package7Ns0Rename/ package_6/package_7/
+package_8/package_9/ package8Ns0Rename/package9Ns0Rename/ package_8/package_9/
+package_10/package_11/ package10Ns0Rename/package11Ns0Rename/ package_10/package_11/
+package_12/package_13/ filler_13/package12Ns0Rename/package13Ns0Rename/ package_12/package_13/
 class_3 package_3/class3Ns0Rename class_3
 package_4/class_4 package_4/class_4 class4Ns1Rename
 package_6/class_6 package_7/class6Ns0Rename package_6/class_6
diff --git a/src/test/resources/reading/holes/xsrg.xsrg b/src/test/resources/reading/holes/xsrg.xsrg
index 6e89784c..f7b08e5e 100644
--- a/src/test/resources/reading/holes/xsrg.xsrg
+++ b/src/test/resources/reading/holes/xsrg.xsrg
@@ -1,3 +1,10 @@
+PK: package_1/ package1Ns0Rename/
+PK: package_2/ package2Ns0Rename/
+PK: package_3/ filler_3/package3Ns0Rename/
+PK: package_6/package_7/ filler_7/package6Ns0Rename/package7Ns0Rename/
+PK: package_8/package_9/ package8Ns0Rename/package9Ns0Rename/
+PK: package_10/package_11/ package10Ns0Rename/package11Ns0Rename/
+PK: package_12/package_13/ filler_13/package12Ns0Rename/package13Ns0Rename/
 CL: class_3 package_3/class3Ns0Rename
 CL: package_6/class_6 package_7/class6Ns0Rename
 CL: class_9$class_10 class_9$class10Ns0Rename
diff --git a/src/test/resources/reading/repeated-elements/csrg.csrg b/src/test/resources/reading/repeated-elements/csrg.csrg
index 0cb26ff5..a19bddb3 100644
--- a/src/test/resources/reading/repeated-elements/csrg.csrg
+++ b/src/test/resources/reading/repeated-elements/csrg.csrg
@@ -1,3 +1,7 @@
+package_1/ package1Ns0Rename0/
+package_1/ package1Ns0Rename/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename0/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 class_1 class1Ns0Rename0
 class_1 class1Ns0Rename
 class_1 field_1 field1Ns0Rename0
diff --git a/src/test/resources/reading/repeated-elements/jobf.jobf b/src/test/resources/reading/repeated-elements/jobf.jobf
index 6fe4125a..48bf2342 100644
--- a/src/test/resources/reading/repeated-elements/jobf.jobf
+++ b/src/test/resources/reading/repeated-elements/jobf.jobf
@@ -1,3 +1,7 @@
+p package_1 = package1Ns0Rename0
+p package_1 = package1Ns0Rename
+p package_1.package_2 = package1Ns0Rename.package2Ns0Rename0
+p package_1.package_2 = package1Ns0Rename.package2Ns0Rename
 c class_1 = class1Ns0Rename0
 c class_1 = class1Ns0Rename
 f class_1.field_1:I = field1Ns0Rename0
diff --git a/src/test/resources/reading/repeated-elements/migration-map.xml b/src/test/resources/reading/repeated-elements/migration-map.xml
index 7f1df594..a15e24da 100644
--- a/src/test/resources/reading/repeated-elements/migration-map.xml
+++ b/src/test/resources/reading/repeated-elements/migration-map.xml
@@ -4,6 +4,10 @@
 	<order value="0"/>
 	<property-with-empty-value value=""/>
 	<property-with-null-value/>
+	<entry oldName="package_1" newName="package1Ns0Rename0" type="package" recursive="false"/>
+	<entry oldName="package_1" newName="package1Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_1.package_2" newName="package1Ns0Rename.package2Ns0Rename0" type="package" recursive="false"/>
+	<entry oldName="package_1.package_2" newName="package1Ns0Rename.package2Ns0Rename" type="package" recursive="false"/>
 	<entry oldName="class_1" newName="class1Ns0Rename0" type="class"/>
 	<entry oldName="class_1" newName="class1Ns0Rename" type="class"/>
 	<entry oldName="class_1$class_2" newName="class1Ns0Rename$class2Ns0Rename0" type="class"/>
diff --git a/src/test/resources/reading/repeated-elements/srg.srg b/src/test/resources/reading/repeated-elements/srg.srg
index 753ad3f2..45f5ec9d 100644
--- a/src/test/resources/reading/repeated-elements/srg.srg
+++ b/src/test/resources/reading/repeated-elements/srg.srg
@@ -1,3 +1,7 @@
+PK: package_1/ package1Ns0Rename0/
+PK: package_1/ package1Ns0Rename/
+PK: package_1/package_2/ package1Ns0Rename/package2Ns0Rename0/
+PK: package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 CL: class_1 class1Ns0Rename0
 CL: class_1 class1Ns0Rename1
 FD: class_1/field_1 class1Ns0Rename/field1Ns0Rename0
diff --git a/src/test/resources/reading/repeated-elements/tsrg.tsrg b/src/test/resources/reading/repeated-elements/tsrg.tsrg
index cf675052..4c4d66e0 100644
--- a/src/test/resources/reading/repeated-elements/tsrg.tsrg
+++ b/src/test/resources/reading/repeated-elements/tsrg.tsrg
@@ -1,3 +1,7 @@
+package_1/ package1Ns0Rename0/
+package_1/ package1Ns0Rename/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename0/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 class_1 class1Ns0Rename0
 class_1 class1Ns0Rename
 	field_1 field1Ns0Rename0
diff --git a/src/test/resources/reading/repeated-elements/tsrgV2.tsrg b/src/test/resources/reading/repeated-elements/tsrgV2.tsrg
index 36cc5e1c..f482c46d 100644
--- a/src/test/resources/reading/repeated-elements/tsrgV2.tsrg
+++ b/src/test/resources/reading/repeated-elements/tsrgV2.tsrg
@@ -1,4 +1,8 @@
 tsrg2 source target target2
+package_1/ package1Ns0Rename0/ package1Ns1Rename0/
+package_1/ package1Ns0Rename/ package1Ns1Rename/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename0/ package1Ns1Rename/package2Ns1Rename0/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename/ package1Ns1Rename/package2Ns1Rename/
 class_1 class1Ns0Rename0 class1Ns1Rename0
 class_1 class1Ns0Rename class1Ns1Rename
 	field_1 I field1Ns0Rename0 field1Ns1Rename0
diff --git a/src/test/resources/reading/repeated-elements/xsrg.xsrg b/src/test/resources/reading/repeated-elements/xsrg.xsrg
index 8a82ca9c..9158b034 100644
--- a/src/test/resources/reading/repeated-elements/xsrg.xsrg
+++ b/src/test/resources/reading/repeated-elements/xsrg.xsrg
@@ -1,3 +1,7 @@
+PK: package_1/ package1Ns0Rename0/
+PK: package_1/ package1Ns0Rename/
+PK: package_1/package_2/ package1Ns0Rename/package2Ns0Rename0/
+PK: package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 CL: class_1 class1Ns0Rename0
 CL: class_1 class1Ns0Rename
 FD: class_1/field_1 I class1Ns0Rename/field1Ns0Rename0 I
diff --git a/src/test/resources/reading/valid/csrg.csrg b/src/test/resources/reading/valid/csrg.csrg
index 2eb1c410..0f9f54f1 100644
--- a/src/test/resources/reading/valid/csrg.csrg
+++ b/src/test/resources/reading/valid/csrg.csrg
@@ -1,3 +1,5 @@
+package_1/ package1Ns0Rename/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 class_1 class1Ns0Rename
 class_1 field_1 field1Ns0Rename
 class_1 method_1 ()I method1Ns0Rename
diff --git a/src/test/resources/reading/valid/jobf.jobf b/src/test/resources/reading/valid/jobf.jobf
index bab02c3b..97314290 100644
--- a/src/test/resources/reading/valid/jobf.jobf
+++ b/src/test/resources/reading/valid/jobf.jobf
@@ -1,3 +1,5 @@
+p package_1 = package1Ns0Rename
+p package_1.package_2 = package1Ns0Rename.package2Ns0Rename
 c class_1 = class1Ns0Rename
 f class_1.field_1:I = field1Ns0Rename
 m class_1.method_1()I = method1Ns0Rename
diff --git a/src/test/resources/reading/valid/migration-map.xml b/src/test/resources/reading/valid/migration-map.xml
index f330e955..21e0e72f 100644
--- a/src/test/resources/reading/valid/migration-map.xml
+++ b/src/test/resources/reading/valid/migration-map.xml
@@ -4,6 +4,8 @@
 	<order value="0"/>
 	<property-with-empty-value value=""/>
 	<property-with-null-value/>
+	<entry oldName="package_1" newName="package1Ns0Rename" type="package" recursive="false"/>
+	<entry oldName="package_1.package_2" newName="package1Ns0Rename.package2Ns0Rename" type="package" recursive="false"/>
 	<entry oldName="class_1" newName="class1Ns0Rename" type="class"/>
 	<entry oldName="class_1$class_2" newName="class1Ns0Rename$class2Ns0Rename" type="class"/>
 	<entry oldName="class_3" newName="package_3.class3Ns0Rename" type="class"/>
diff --git a/src/test/resources/reading/valid/srg.srg b/src/test/resources/reading/valid/srg.srg
index 95ca6759..d918aa5f 100644
--- a/src/test/resources/reading/valid/srg.srg
+++ b/src/test/resources/reading/valid/srg.srg
@@ -1,3 +1,5 @@
+PK: package_1/ package1Ns0Rename/
+PK: package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 CL: class_1 class1Ns0Rename
 FD: class_1/field_1 class1Ns0Rename/field1Ns0Rename
 MD: class_1/method_1 ()I class1Ns0Rename/method1Ns0Rename ()I
diff --git a/src/test/resources/reading/valid/tsrg.tsrg b/src/test/resources/reading/valid/tsrg.tsrg
index 6e751643..8b9a74f1 100644
--- a/src/test/resources/reading/valid/tsrg.tsrg
+++ b/src/test/resources/reading/valid/tsrg.tsrg
@@ -1,3 +1,5 @@
+package_1/ package1Ns0Rename/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 class_1 class1Ns0Rename
 	field_1 field1Ns0Rename
 	method_1 ()I method1Ns0Rename
diff --git a/src/test/resources/reading/valid/tsrgV2.tsrg b/src/test/resources/reading/valid/tsrgV2.tsrg
index d383ea71..a5e04e8c 100644
--- a/src/test/resources/reading/valid/tsrgV2.tsrg
+++ b/src/test/resources/reading/valid/tsrgV2.tsrg
@@ -1,4 +1,6 @@
 tsrg2 source target target2
+package_1/ package1Ns0Rename/ package1Ns1Rename/
+package_1/package_2/ package1Ns0Rename/package2Ns0Rename/ package1Ns1Rename/package2Ns1Rename/
 class_1 class1Ns0Rename class1Ns1Rename
 	field_1 I field1Ns0Rename field1Ns1Rename
 	method_1 ()I method1Ns0Rename method1Ns1Rename
diff --git a/src/test/resources/reading/valid/xsrg.xsrg b/src/test/resources/reading/valid/xsrg.xsrg
index 0123a1ea..ed4a56b9 100644
--- a/src/test/resources/reading/valid/xsrg.xsrg
+++ b/src/test/resources/reading/valid/xsrg.xsrg
@@ -1,3 +1,5 @@
+PK: package_1/ package1Ns0Rename/
+PK: package_1/package_2/ package1Ns0Rename/package2Ns0Rename/
 CL: class_1 class1Ns0Rename
 FD: class_1/field_1 I class1Ns0Rename/field1Ns0Rename I
 MD: class_1/method_1 ()I class1Ns0Rename/method1Ns0Rename ()I