A new Internet-Draft, The IANA XML Registry, proposes creating a registry and a new type of URN for XML document types created by IETF standards.

Unlike the XML.org and BizTalk repositories, the IANA XML Registry would only be used for XML DTDs, namespaces, XML Schemas, and RDF Schemas created by the IETF's own projects.

To reference the contents of the repository, the IANA would assign URNs "of the form urn:iana:xml:class:id".

The draft explicitly states that "The URN assigned by the IANA can be used as the value of the SYSTEM identifier," raising issues of compatibility with validating processors which can't resolve URNs. This possibility appears to have been left open by the XML 1.0 Recommendation, however.