Link to mediawiki.org in a message
It's the first time, as I remember, that I see a link to mediawiki.org in a message. MediaWiki:Twocolconflict-preference-enabled. Shouldn't translation be without links? In order to respect the choice of a single Wiki to have links that point out or not?
The namespace prefixe "MediaWiki:" is where translated messages are loaded on all wikis using MetaWiki. It is not goring to Mediawiki.org. You make a confusion with the "mw:" interwiki prefix (and anyway, that prefix is usually not used: when a message needs to reference the MediaWiki.org website, it uses a plain URL (This is generally limited to a few links for shwoing the documentation of Mediawiki or getting support for it).