http://www.ietf.org/rfc/rfc2376.txt
This document proposes two new media subtypes, text/xml and
application/xml, for use in exchanging network entities which are
conforming Extensible Markup Language (XML). XML entities are
currently exchanged via the HyperText Transfer Protocol on the World
Wide Web, are an integral part of the WebDAV protocol for remote web
authoring, and are expected to have utility in many domains.