Recent changes, new pages, watchlist and history: $wgWatchlistPurgeRate
The per-edit rate at which expired watchlist items will be purged from the database.
Introduced in version:1.35.0 (Gerrit change 572147; git #83804ad)
Removed in version:still in use
Allowed values:0.0–1.0 (float)
Default value:0.1

Chance of expired watchlist items being purged on any page edit.

Only has effect if $wgWatchlistExpiry is true.

If this is zero, expired watchlist items will not be removed and the purgeExpiredWatchlistItems.php maintenance script should be run periodically.

See also edit