Board Thread:Support Requests - Getting Technical/@comment-31513065-20200512021819/@comment-9605025-20200512030326

The MediaWiki pages are not the issue. After all, you were able to edit MediaWiki:ImportJS. MediaWiki pages are used for a cariety ofthings which includes but is not limited to custom JS. It is custom JS, not MediaWiki pages, that is currently not working on UCP wikis.

That said, yes and no. Technically speaking, all MediaWiki pages are "working". What I think you meant to ask was which ones you can edit. Unfortunately, UCP is still under development so Fandom has not released many details about the various features. For security reasons, Fandom restricts which MediaWiki pages local admins can edit. The list of MediaWiki pages local admins can edit is called the whitelist. Fandom has not yet told us what the whitelist is for UCP wikis.

One thing we do know is that there have been some significant changes. For instance, on older wikis, you could use MediaWiki:User-identity-box-group-sysop to set a custom text for the "Admin" tag that appears in an admin's masthead. There are similar pages for user groups like content moderators, chat moderators, bureaucrats, etc. However, none of these pages exist on UCP wikis; at least not yet.