See the parent task.
Customize query in gerrit
|Open||None||T232867 Hooks listed as deprecated in MediaWiki should actually be deprecated (and vice versa)|
|Resolved||Ladsgroup||T232875 The "ResourceLoaderTestModules" hook is listed in documentation as deprecated but doesn't emit deprecation warnings yet|
|Resolved||Ladsgroup||T259697 Migrate ResourceLoaderTestModules hook in Wikibase to QUnitTestModule|
These patches won't finish it but it fixes everything up to the point of the need to use package modules. For that, I will do something slightly complicated so let's first get these in and then we move to that one.