The RSS namespace is defined by the URI http://purl.org/rss/1.0/ as well. The address of the RDF validators is http://www.w3.org/RDF/Validator/. John Reagle created the Relax NG schema, which is used to explain the elements. The URI is http://www.w3.org/2002/09/rss-rng/. It was transferred with Trang in the complete Relax NG syntax, and was revised slightly.
As protocol schemas for URIs, RSS 1.0 only allows
http:, https:, ftp:, and
mailto: within text-input fields.
Concerning the MIME type, the specification talks about
A certain data extension is not necessary;
.xml and—preferably—.rdf are recommended.
Document element of an RSS 1.0 element.
element rdf:RDF ...