from HTML WG comments:

- Guideline 3.5

This only addresses things like alternative text such that you could render
the alternative text alone and that would be adequate for the content user.
This guideline should be extended or a new guideline should be added to
include ANY accessibility related meta data. This will include Role meta
data in xhtml 2, XForms labels, XML event descriptions, upcoming state
attributes from the WAI PF working group. The role is not considered an
"alternative equivalent" as stated. Other information such as state data
are required for things like check boxes. This has a WCAG 1.0 flavor and
does not include new content being created which provides for improved
semantics.