**User story:** As an editor with a very large number of pages on my Watchlist, I want to remove a substantial percentage of them that I'm no longer interested in watching, so that it can be a more manageable size.
Many of Wikimedia's most active editors have developed extremely large watchlists (where 'large' means more than a few thousand pages, some as many as hundreds of thousands). It is impractical (and sometimes impossible - T41510) for these users to remove pages one-by-one to reduce the size of their watchlist back to a manageable number of pages.
One straightforward solution could be to build a simple tool that allows users to log in via OAuth and have pages removed from their watchlist according to some criteria they can set.
The tool could use the [[ https://www.mediawiki.org/wiki/API:Watchlistraw | Watchlistraw ]] API to retrieve all the pages on the user's watchlist, then go through page-by-page to see if meets the criteria they set, and remove it from their watchlist if so.
Criteria could include:
* Pages that are deleted and haven't existed in some period of time
* Pages the user hasn't edited in some period of time
* Pages the user has only ever made 1 edit to, where that edit is a revert