Add notes about schema extraction

README.md

@@ -40,6 +40,41 @@ json = kcidb_io.new()
 kcidb_io.schema.validate(json)
 ```
 
+Exporting the JSON schema
+-------------------------
+
+The current schema is available as a JSON Schema dictionary on the version
+class. The latest schema is exposed as `kcidb_io.schema.LATEST`.
+
+Export the latest schema to a file:
+
+```bash
+python3 - <<'PY'
+import json
+from kcidb_io import schema
+
+v = schema.LATEST
+with open(f"kcidb-io.schema.v{v.major}.{v.minor}.json", "w") as f:
+    json.dump(v.json, f, indent=2, sort_keys=True)
+PY
+```
+
+Compatibility notes
+-------------------
+
+The schema is validated in this library using JSON Schema Draft-07. The
+exported schema JSON does not include a `$schema` field; if a validator
+requires one, add:
+
+```json
+{
+  "$schema": "http://json-schema.org/draft-07/schema#"
+}
+```
+
+The schema uses `$defs` and the `uri` string format. If your validator supports
+format checking, enable it to validate `uri` values.
+
 Hacking
 -------