diff --git a/src/format.js b/src/format.js
index f65fb16901..db9269ef4d 100644
--- a/src/format.js
+++ b/src/format.js
@@ -14,7 +14,7 @@ const weekdayFormat = memoize1((locale, weekday) => {
   return new Intl.DateTimeFormat(locale, {timeZone: "UTC", ...(weekday && {weekday})});
 });
 
-export function formatNumber(locale = "en-US") {
+function formatNumber(locale) {
   const format = numberFormat(locale);
   return (i) => (i != null && !isNaN(i) ? format.format(i) : undefined);
 }
@@ -33,7 +33,7 @@ export function formatIsoDate(date) {
   return isoFormat(date, "Invalid Date");
 }
 
-export function formatAuto(locale = "en-US") {
+function formatAuto(locale = "en-US") {
   const number = formatNumber(locale);
   return (v) => (v instanceof Date ? formatIsoDate : typeof v === "number" ? number : string)(v);
 }
diff --git a/src/options.js b/src/options.js
index 387daa94fb..15dff988e6 100644
--- a/src/options.js
+++ b/src/options.js
@@ -50,12 +50,10 @@ export const singleton = [null]; // for data-less decoration marks, e.g. frame
 export const field = (name) => (d) => d[name];
 export const indexOf = {transform: range};
 export const identity = {transform: (d) => d};
-export const zero = () => 0;
 export const one = () => 1;
 export const yes = () => true;
 export const string = (x) => (x == null ? x : `${x}`);
 export const number = (x) => (x == null ? x : +x);
-export const boolean = (x) => (x == null ? x : !!x);
 export const first = (x) => (x ? x[0] : undefined);
 export const second = (x) => (x ? x[1] : undefined);
 export const third = (x) => (x ? x[2] : undefined);
@@ -225,11 +223,6 @@ export function range(data) {
   return r;
 }
 
-// Returns a filtered range of data given the test function.
-export function where(data, test) {
-  return range(data).filter((i) => test(data[i], i, data));
-}
-
 // Returns an array [values[index[0]], values[index[1]], …].
 export function take(values, index) {
   return map(index, (i) => values[i], values.constructor);
@@ -528,7 +521,7 @@ export function inherit(options = {}, ...rest) {
 
 // Given an iterable of named things (objects with a name property), returns a
 // corresponding object with properties associated with the given name.
-export function named(things) {
+function named(things) {
   console.warn("named iterables are deprecated; please use an object instead");
   const names = new Set();
   return Object.fromEntries(
diff --git a/src/scales/index.js b/src/scales/index.js
index ee2f2b2688..fd08c77bb3 100644
--- a/src/scales/index.js
+++ b/src/scales/index.js
@@ -24,7 +24,7 @@ export const symbol = Symbol("symbol");
 
 // There isn’t really a projection scale; this represents x and y for geometry.
 // This is used to denote channels that should be projected.
-export const projection = Symbol("projection");
+const projection = Symbol("projection");
 
 // TODO Rather than hard-coding the list of known scale names, collect the names
 // and categories for each plot specification, so that custom marks can register
diff --git a/src/stats.js b/src/stats.js
index e4fee82f05..91b5889e8c 100644
--- a/src/stats.js
+++ b/src/stats.js
@@ -20,7 +20,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-export function ibetainv(p, a, b) {
+function ibetainv(p, a, b) {
   var EPS = 1e-8;
   var a1 = a - 1;
   var b1 = b - 1;
@@ -60,7 +60,7 @@ export function ibetainv(p, a, b) {
   return x;
 }
 
-export function ibeta(x, a, b) {
+function ibeta(x, a, b) {
   // Factors in front of the continued fraction.
   var bt =
     x === 0 || x === 1 ? 0 : Math.exp(gammaln(a + b) - gammaln(a) - gammaln(b) + a * Math.log(x) + b * Math.log(1 - x));
@@ -72,7 +72,7 @@ export function ibeta(x, a, b) {
   return 1 - (bt * betacf(1 - x, b, a)) / b;
 }
 
-export function betacf(x, a, b) {
+function betacf(x, a, b) {
   var fpmin = 1e-30;
   var m = 1;
   var qab = a + b;
@@ -112,7 +112,7 @@ export function betacf(x, a, b) {
   return h;
 }
 
-export function gammaln(x) {
+function gammaln(x) {
   var j = 0;
   var cof = [
     76.18009172947146, -86.5053203294167, 24.01409824083091, -1.231739572450155, 0.1208650973866179e-2,
diff --git a/src/style.js b/src/style.js
index a1af100fcd..98ae865130 100644
--- a/src/style.js
+++ b/src/style.js
@@ -147,7 +147,7 @@ export function styles(
 }
 
 // Applies the specified titles via selection.call.
-export function applyTitle(selection, L) {
+function applyTitle(selection, L) {
   if (L)
     selection
       .filter((i) => nonempty(L[i]))
@@ -156,7 +156,7 @@ export function applyTitle(selection, L) {
 }
 
 // Like applyTitle, but for grouped data (lines, areas).
-export function applyTitleGroup(selection, L) {
+function applyTitleGroup(selection, L) {
   if (L)
     selection
       .filter(([i]) => nonempty(L[i]))
@@ -164,11 +164,11 @@ export function applyTitleGroup(selection, L) {
       .call(applyTextGroup, L);
 }
 
-export function applyText(selection, T) {
+function applyText(selection, T) {
   if (T) selection.text((i) => formatDefault(T[i]));
 }
 
-export function applyTextGroup(selection, T) {
+function applyTextGroup(selection, T) {
   if (T) selection.text(([i]) => formatDefault(T[i]));
 }
 
@@ -387,7 +387,7 @@ export function applyAttr(selection, name, value) {
   if (value != null) selection.attr(name, value);
 }
 
-export function applyStyle(selection, name, value) {
+function applyStyle(selection, name, value) {
   if (value != null) selection.style(name, value);
 }
 
@@ -403,7 +403,7 @@ export function impliedString(value, impliedValue) {
   if ((value = string(value)) !== impliedValue) return value;
 }
 
-export function impliedNumber(value, impliedValue) {
+function impliedNumber(value, impliedValue) {
   if ((value = number(value)) !== impliedValue) return value;
 }
 
diff --git a/src/time.js b/src/time.js
index 63722f587c..630260552b 100644
--- a/src/time.js
+++ b/src/time.js
@@ -110,7 +110,7 @@ const utcIntervals = new Map([
 // interval; that would allow us to move this logic to D3, and allow
 // generalization even when a custom interval is provided.
 export const intervalDuration = Symbol("intervalDuration");
-export const intervalType = Symbol("intervalType");
+const intervalType = Symbol("intervalType");
 
 // We greedily mutate D3’s standard intervals on load so that the hidden fields
 // are available even if specified as e.g. d3.utcMonth instead of "month".