Where does the "access declaration" metadata requirement belong?

Several weeks ago the working group resolved (1) to delete the success
criteria at level 2 that require the making of conformance claims,
while retaining the substantive review requirements, and (2) to add a
level 3 requirement that metadata be provided to make accessible
content easier to locate and identify.

The first part is easy to implement: it simply involves deleting the
pertinent text from the document. The second part requires a proposal.
It isn't clear to me under which checkpoint this belongs. Are there
any suggestions? It was agreed at the meeting that the new success
criterion should be introduced at level 3. Although there was some
suggestion that guideline 5 might be an appropriate rubric, I can't
find any checkpoint under guideline 5 (or under guideline 3 -
navigation) that seems suitable. The new success criterion would be
along the following lines:

Metadata associated with the content assert a claim of conformance to
these guidelines.

Note: see the conformance section for precise details of the
information that must be included in a conformance claim.