diff --git a/README.md b/README.md
index 4b3c25c16..7bf8ec73e 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Python Package: Pypi or conda
 Gallery of Notebooks
 --------------------
 
-[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ecmwf/notebook-examples.git/master)
+[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ecmwf/notebook-examples/master?filepath=%2Fhome%2Fjovyan%2Fvisualisation)
 
 
 Docker Image
diff --git a/tools/xref.py b/tools/xref.py
new file mode 100755
index 000000000..72aaaea35
--- /dev/null
+++ b/tools/xref.py
@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+import os
+import xmltodict
+import json
+from collections import defaultdict
+
+DEFS = {}
+
+
+def load(n):
+    with open(n) as f:
+        x = xmltodict.parse(f.read())
+
+    klass = x['magics']['class']
+    klass['PATH'] = n
+
+    assert klass['@name'] not in DEFS, (klass['@name'], n, DEFS[klass['@name']])
+    DEFS[klass['@name']] = klass
+
+    # if '@inherits' in klass:
+    #     return
+
+    # try:
+    #     assert False
+    #     print(klass['@name'])
+    # except:
+    #     print(json.dumps(x, indent=4))
+    #     exit(1)
+
+
+for n in sorted(os.listdir('.')):
+    if n.endswith('.xml'):  # and n.startswith("SimpleP"):
+        load(n)
+
+
+def action(klass):
+    if '@action' in klass:
+        return klass['@action']
+    if '@inherits' in klass:
+        if '/' in klass['@inherits']:
+            return [action(x) for x in klass['@inherits'].split('/')]
+        return action(DEFS[klass['@inherits']])
+
+
+PARAMS = defaultdict(set)
+for n, klass in DEFS.items():
+    parms = klass.get('parameter', [])
+    if not isinstance(parms, list):
+        parms = [parms]
+    for p in parms:
+
+        try:
+            PARAMS[p['@name']].add(action(klass))
+        except:
+            print(klass)
+            raise
+    # print(n, action(klass))
+    # if '@action' in klass:
+    #     print(n, json.dumps(klass, indent=4))
+# load("Contour.xml")
+
+for p, v in sorted(PARAMS.items()):
+    print(p, v)