This version of XHTML provides a definition of strictly conforming XHTML 1.0 documents, which are restricted to elements and attributes from the XML and XHTML 1.0 namespaces. See Section 3.1.2 for information on using XHTML with other namespaces, for instance, to include metadata expressed in RDF within XHTML documents.
The mission of this Working Group is to complement the concrete RDF/XML syntax with a mechanism to relate other XML syntaxes (especially XHTML dialects or "microformats") to the RDF abstract syntax via transformations identified by URIs.