When I add "$anchor" to my JSON Schema, the Oxygen editor gives this error message: The keyword "$anchor" is not part of JSON Schema Draft 2020-12 specification. Therefore, it is ignored by the validation engine. But that's not true. See section 8.2.2 of the 2020-12 specification (https://json-schema.org/draft/2020-12/json-schema-core.html#section-8.2.2): Using JSON Pointer fragments requires knowledge of the structure of the schema. When writing schema documents with the intention to provide re-usable schemas, it may be preferable to use a plain name fragment that is not tied to any particular structural location. This allows a subschema to be relocated without requiring JSON Pointer references to be updated. The "$anchor" and "$dynamicAnchor" keywords are used to specify such fragments. They are identifier keywords that can only be used to create plain name fragments, rather than absolute URIs as seen with "$id"...