Fossil currently always delivers web page content as text/html to the browser.
Following the guidelines in <a href="http://www.w3.org/TR/xhtml-media-types/">http://www.w3.org/TR/xhtml-media-types/</a> the attached patch delivers the application/xhtml+xml content type instead when appropriate.
This will allow the use of the <nowiki><![CDATA[ ... anything not escaped ... ]]></nowiki> construct in future fossil output which should facilitate embedding arbitrary command output into the returned web pages (such as for rebuild and sync when used from the web ui).
NOTE: The patch attached to ticket [5ff2043c96] should also be applied or else invalid xhtml can be sent to the browser.