[Stolen from https://www.mediawiki.org/wiki/Topic:Uu9mfg05l7zcicdd.]
It would be lovely to add a filter group for RecentChanges/Watchlists for Wikibase edits based on type of edit:
For the above four, you'd probably want to filter explicitly on adds/changes/removes, and on a match list of languages (maybe pre-populated from the user's Babel stack)?
For this, you'd want add/changes/removes, but also details within changes like added/removed qualifiers, and possibly match to a list of properties (e.g. show me changes that remove instanceOf claims).
From my poking around the DBs, this is going to be a serious epic if we do this. Wikibase doesn't store any of this information inside the DB stack, instead calculating it on the fly from deserialised entities fetched from external storage, so there's nothing in the recentchanges table for the filtering code to use, nor anything even to join onto.