This is mostly for the use of editor enhancement userscripts.

Prior to the RDFa removal, we could find catalogue numbers on pages by looking for <span> tags with the "mo:catalogue_number" property. I used this in some user scripts to add some extra hooks and lookups on Japanese-specific formatted catalogue numbers.

The script no longer functions, and now there's not really any good way of finding catalogue numbers on the page other than fragile contextual matching. Simply sticking the catalogue number in a span with some unique class would help...

This affects the release page itself, and it would also be nice to have it on pages that list releases - e.g. release group page, artist release list, label release list, search results.