The applicability document says that getMetadata should return RDF.
Because getMetadata returns XML, the applicability document is
implicitly requiring a specific mapping from RDF to XML. I wonder
whether the serialization of RDF as XML is an accepted standard, or
whether the requirement for RDF needs clarification.
Possibly the applicability document should explicitly refer to
appropriate schemas and/or namespaces. For example, the XML documents
produced by my LSID getMetadata services start with an rdf:RDF tag that
specifies a variety of namespaces. Those namespaces, plus some implicit
XML schema, constrain the serialization of the RDF triples.
Please comment on whether the applicability document requires
additional detail to specify the XML representation of RDF documents
that are produced by getMetadata.