Dan Connolly wrote:
...
It wasn't a problem at all before HTML 5, because each spec for
text/html pretty much said "all existing HTML standards are fine".
It might not be (much of) a problem in HTML 5 either; I'm not
sure that "*the HTML syntax* doesn't include doctypes that are widely
used in documents that conform to HTML 2, 3.2, and 4.x specs and XHTML
1.x specs" since Anne helped me find the "obsolete permitted
DOCTYPE" stuff.
...
Wait, the doctype is just a small part of the issue.
The main issue (IMHO) is that the proposed re-registration of text/html
can make existing HTML4 documents invalid; for instance, because of the
removal of attributes), and this is something RFC 4288 explicitly forbids:
Media type registrations may not be deleted; media types that are no
longer believed appropriate for use can be declared OBSOLETE by a
change to their "intended use" field; such media types will be
clearly marked in the lists published by the IANA.
<http://tools.ietf.org/html/rfc4288#section-9>
Best regards, Julian
