With #705 and #706 and #cross we added cross entry references (both for data and schema, e.g. `m_def`). Currently, only the processing is resolving these references (via `nomad/datamodel/context.py::ServerContext). Similar implementations are still necessary for: - client use (e.g. with ArchiveClient) - command line use (e.g. running parsers with `nomad parse`) - when the archive reader is implements the required reference resolution features Check the metainfo/archive documentation, especially https://nomad-lab.eu/prod/v1/docs/metainfo.html#references-and-proxies to get an idea about the concepts. Check `tests/datamodel/test_context.py` to get an idea about the implementation.