As described in w3c/aria#500, there is a need to prohibit the exposure of the value of aria-roledescription for certain HTML elements (e.g. div and span) when there is no explicit or implicit ARIA role. Alternatively, or in addition, this AAM could explicitly allow the exposure of the value of aria-roledescription on certain elements (an example from HTML would be meter used without an explicit role).

The purpose/motivation behind this request is that we want to strongly discourage authors from using aria-roledescription on elements which lack useful semantic meaning, and we want to strongly encourage (and perhaps insist) that user agents do not expose the value of aria-roledescription when it is used on an element which lacks useful semantic meaning and also lacks an implicit or explicit ARIA role. But there's no way we can come up with a host-language-agnostic, universally-agreed-upon definition of "useful semantic meaning" or "generic element." If such elements are explicitly identified in the host-language-specific AAMs, we (ARIA spec and/or Core AAM) should be able to point authors and user agents to those specs to get the implementation and user experience desired and intended for aria-roledescription.

Note: As @stevefaulkner suggested, I opened w3c/html-aria#77. But the HTML AAM already has a per-element mapping table with comments, so perhaps this information could be added there?? (Asking is, they say, free. 😉)