Watchlists can be accessed via rss/atom feeds as described in https://www.mediawiki.org/wiki/API:Watchlist_feed. Feeds can already be customized with a bunch of URL parameters. Unfortunately, there is no option available yet to fetch the feed with diff links to the mobile frontend instead of the desktop frontend. When the watchlist feed is used on mobile (small screen) devices, it would be very useful to have a feed parameter to toggle to mobile frontend diff links.
Expected behavior: when used with &mobileview=1 (or similar parameter name), the feed comes with diff links like https://m.wikidata.org/w/index.php?title=xyz&diff=123 instead of https://www.wikidata.org/w/index.php?title=xyz&diff=123. I guess the same behavior can easily be implemented for other projects than Wikidata, of course.