All values are now allowed for the role attribute.
* $wgContentHandlers now also supports callbacks to create an instance of the
appropriate ContentHandler subclass.
+* Added $wgAuthenticationTokenVersion, which if non-null prevents the
+ user_token database field from being exposed in cookies. Setting this would
+ be a good idea, but will log out all current sessions.
+* $wgEventRelayerConfig was added, for managing PubSub event relay configuration,
+ specifically for reliable CDN url purges.
=== External library changes in 1.27 ===