https://www.mediawiki.org/wiki/Watchlist_Expiry is a great start, but there are still a few loose ends:
- Move Watchlist Expiry to Help:Watchlist expiry (all end user documentation belongs in the Help namespace and the page name should use sentence case rather than title case). Note that because the page is translatable, you will need to get a translation administrator (such as Johan) to perform the actual move.
- Add mention of watchlist expiry to Help:Watchlist with appropriate links.
- Add mention of watchlist expiry to Help:Watching pages with appropriate links.
- Add technical documentation for watchlist expiry to Manual:Watchlist (or a new Manual:Watchlist_expiry page).
- Add technical documentation for watchlist expiry to Manual:watchlist_expiry table
- Add technical documentation for watchlist expiry to Manual:purgeExpiredWatchlistItems.php
- Add technical documentation for watchlist expiry to Manual:$wgWatchlistExpiry
- Add technical documentation for watchlist expiry to Manual:$wgWatchlistPurgeRate
- Add technical documentation for watchlist expiry to Manual:$wgWatchlistExpiryMaxDuration
Be sure to use {{MW 1.35|+}} where appropriate.