Board Thread:Support Requests - Getting Technical/@comment-17033657-20140608231923/@comment-366087-20140608235629

You might try either MediaWiki:BlankPage or MediaWiki:Createpage-with-video …both of these are seen as options from the Contribute>Add a page dropdown. Changing those MW pages will affect all new page layouts of those types.

Or are you looking for that header box on *every* page? What exactly are you trying to accomplish? What would that "articletext" say or do?