uses are in active use.
&$tags: list of all active tags. Append to this array.
+'ChangeTagsAfterUpdateTags': Called after tags have been updated with the
+ChangeTags::updateTags function. Params:
+$addedTags: tags effectively added in the update
+$removedTags: tags effectively removed in the update
+$prevTags: tags that were present prior to the update
+$rc_id: recentchanges table id
+$rev_id: revision table id
+$log_id: logging table id
+$params: tag params
+$rc: RecentChange being tagged when the tagging accompanies the action or null
+$user: User who performed the tagging when the tagging is subsequent to the action or null
+
'Collation::factory': Called if $wgCategoryCollation is an unknown collation.
$collationName: Name of the collation in question
&$collationObject: Null. Replace with a subclass of the Collation class that