There are several way to inject these meta-markers:
- hard-code knowedge about the respective markers into the serializers
- make the serializers depend on MediaWiki API code
- inject a callback for post-processing substructures, which could be used to inject the meta-markers.
- use a decorator to post-processing substructures, to inject the meta-markers.
- post-process the complete data structure representing an entity, injecting the markers in the appropriate places