This might be an epic task that is very hard to fix but let's document this problem at least in public.
This is one outcome from T113378: Lessons learned from the first Gerrit Cleanup Day.
There seems to be unclear responsibility for some parts of MediaWiki core so nobody looks at its proposed changes in Gerrit.
- "New core team?" meeting: Etherpad log from Wikimedia Developer Summit, 2016-01-06 unconference day
- T149533#2956629 from Wikimedia Developer Summit 2017
Internal / non-public WMF page that brought up the topic of WMF's Core maintenance
- Old MW Core team page with its responsibilities