* Style tags with a 'data-mw-deduplicate' attribute will be deduplicated as a
ParserOutput::getText() post-cache transformation. This may be disabled by
passing 'deduplicateStyles' => false to that method.
+* The identity of the logged-in or IP "actor" for logged actions is being moved
+ into a new actor table, with the rows in tables such as revision and logging
+ referring to the actor ID instead of storing the user ID and name/IP in
+ every row.
+ * This is currently gated by $wgActorTableSchemaMigrationStage. Most wikis
+ can set this to MIGRATION_NEW and run maintenance/migrateActors.php as
+ soon as any necessary extensions are updated.
+ * Most code accessing rows for logged actions from the database should use
+ the relevant getQueryInfo() methods to get the information needed to build
+ the SQL query. The ActorMigration class may also be used to get feature-flagged
+ information needed to access actor-related fields during the migration
+ period.
=== External library changes in 1.31 ===