Thanks for noticing! Pages in message namespaces don't get categorized like normal pages. We should figure out a way to do that, or to list those page some other way.
You can still list pages in the message namespaces (whose contents are not normal Mediawiki pages and cannot be modified by inserting a deletion request template) by posting a message to the Support page. For now, there's no other way for users to add metadata to mark and track those message pages for discussion (even if this wiki supports some metadata extensions, with SemanticMetaWiki or page content types, those extensions are still not defining any way such maintenance requests).