Currently GlobalWatchlist.js users can filter edits by user registrations status, whether a edit is minor or not etc by setting up a their preferences in Special:BlankPage/GlobalWatchlistConfig much like the subsection "Changes shown" in Special:Preferences#mw-prefsection-watchlist.

If a user want to use a different filter temporarily or save multiple filters. They have no way of doing that. (unless they copy the config from global.js.)
Local watchlist provides a UI with more options to filter edits. Such as filtering by namespace, tags, etc.

The purpose of this task is to investigate how to implement these features, and which should be implemented. Subtasks should be created if we decide to implement this.