This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
From the current draft: "XML documents that use elements or attributes from the HTML namespace and that are served over the wire (e.g. by HTTP) must be sent using an XML MIME type such as application/xml or application/xhtml+xml and must not be served as text/html. [RFC3023]" This makes it appear that serving polyglot documents as text/html is not allowed. I don't believe that's the intent. Perhaps the sentence should be struck. Perhaps the intent it so reinforce the idea that comforming HTML5 user agents will process polyglot documents which are served as text/html by HTML5 parsing rules as opposed to XML parsing rules. Either way, this needs to be clarified.
EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Accepted Change Description: see diff given below Rationale: Concurred with reporter's comments.
Checked in as WHATWG revision r4459. Check-in comment: Remove text that barred HTML source code from being sent as text/plain, and other such things. http://html5.org/tools/web-apps-tracker?from=4458&to=4459