debug mode: wfMsg, wfMsgNoTrans, wfMsgForContent, wfMsgForContentNoTrans,
wfMsgReal, wfMsgGetKey, wfMsgHtml, wfMsgWikiHtml, wfMsgExt, wfEmptyMsg. Use
the Message class, or the global method wfMessage.
+* Debug message emitted by wfDebugLog() will now be prefixed with the group
+ name when its logged to the default log file. That is the case whenever the
+ group has no key in wgDebugLogGroups, that will help triage the default log.
+* (bug 24620) Add types to LogFormatter.
+* jQuery JSON upgraded from 2.3 to 2.4.0.
=== Bug fixes in 1.21 ===
* (bug 40353) SpecialDoubleRedirect should support interwiki redirects.