* Deleted DatabaseMysql.php, no longer necessary, database classes are autoloaded.
* Moved wfGetMimeMagic() to MimeMagic::singleton()
* Fixed a couple of __CLASS__.'::'.__FUNCTION__ things.
* Made lines from initialiseMessages() appear as list items during installation
* Moved the bulk of the localisation data from the Language*.php files to the Messages*.php files. Deleted most of the Languages*.php files.
* Introduced "stub global" framework to provide deferred initialisation of core modules.
* Removed placeholder values for $wgTitle and $wgArticle, these variables will now be null during the initialisation process, until they are set by index.php or another entry point.
* Added DBA cache type, for BDB-style caches.
* Removed custom date format functions, replacing them with a format string in the style of PHP's date(). Used string identifiers instead of integer identifiers, in both the language files and user preferences. Migration should be transparent in most cases.
* Simplified the initialisation API for LoadBalancer objects.
* Removed the broken altencoding feature.
* Moved default user options and toggles from Language to User. Language objects are still able to define default preference overrides and extra user toggles, via a slightly different interface.
* Don't include the date option in the parser cache rendering hash unless $wgUseDynamicDates is enabled.
* Merged LanguageUtf8 with Language. Removed LanguageUtf8.php.
* Removed inclusion of language files from the bottom of Language.php. This is now consistently done from Language::factory().
* Add the name of the executing maintenance script to the debug log. Start the profiler during maintenance scripts.
* Added "serialized" directory, for storing precompiled data in serialized form.
* remove require_once() throughout whole code, yet left in few places
* move global functions in HttpUtils, ProxyTools, Credits to class methods
* php5 only: __autoload() now used, combined with class->file map and require()
* move initialization of $wgValidSkinNames to Skin::getSkinNames()
* few more changes that will surely break stuff.
* DB_WRITE now called DB_MASTER, DB_READ now called DB_SLAVE
* Converted to use SQL wrapper functions instead of direct SQL in various places
* Experimental method for preserving the chronological order of events when slave servers are used. Untested.
* Fixes to the new post-parse existence test feature
* Some.. other stuff
available. Currently using for the message cache to avoid reading
every message separately. This now is only slightly slower than
memcached in my tests when $wgUseDatabaseMessages is enabled, so
it's a bit of a speedup for common hosts.