RFC 3236 (rfc3236) - Page 3 of 8
The 'application/xhtml+xml' Media Type
Alternative Format: Original Text Document
RFC 3236 The 'application/xhtml+xml' Media Type January 2002
Although conformant 'application/xhtml+xml' interpreters can
expect that content received is well-formed XML (as defined in
[XML]), it cannot be guaranteed that the content is valid XHTML
(as defined in [XHTML1]). This is in large part due to the
reasons in the preceding paragraph.
Published specification:
XHTML 1.0 is now defined by W3C Recommendation; the latest
published version is [XHTML1]. It provides for the description of
some types of conformant content as "text/html", but also doesn't
disallow the use with other content types (effectively allowing
for the possibility of this new type).
Applications which use this media type:
Some content authors have already begun hand and tool authoring on
the Web with XHTML 1.0. However that content is currently
described as "text/html", allowing existing Web browsers to
process it without reconfiguration for a new media type.
There is no experimental, vendor specific, or personal tree
predecessor to 'application/xhtml+xml'. This new type is being
registered in order to allow for the expected deployment of XHTML
on the World Wide Web, as a first class XML application where
authors can expect that user agents are conformant XML 1.0 [XML]
processors.
Additional information:
Magic number:
There is no single initial byte sequence that is always present
for XHTML files. However, Section 5 below gives some
guidelines for recognizing XHTML files. See also section 3.1 in
[XMLMIME].
File extension:
There are three known file extensions that are currently in use
for XHTML 1.0; ".xht", ".xhtml", and ".html".
It is not recommended that the ".xml" extension (defined in
[XMLMIME]) be used, as web servers may be configured to
distribute such content as type "text/xml" or
"application/xml". [XMLMIME] discusses the unreliability of
this approach in section 3. Of course, should the author
desire this behaviour, then the ".xml" extension can be used.
Baker & Stark Informational