&$tables: array of tables to be queried
&$join_conds: join conditions for the tables
&$fields: array of query fields
-$values: array of variables with watchlist options
+$opts: A FormOptions object with watchlist options for the current request
'SpecialWatchlistGetNonRevisionTypes': Called when building sql query for
SpecialWatchlist. Allows extensions to register custom values they have