2.1.1 [W3C-XSLT] Section 1, Introduction


The specification states:

 The MIME media types text/xml and application/xml should be used for 
 XSLT stylesheets. It is possible that a media type will be registered specifically
 for XSLT stylesheets; if and when it is, that media type may also be used.


An XML style sheet is transformed only when type="text/xsl". XML style sheets of type="text/xml" or of type="application/xml" are not transformed.


Processing instructions for XML style sheets are supported, but an XML style sheet is not automatically associated with XML content.