Feature summary: I'd like to request that content pages (main, draft, template, ...) be given their own MediaWiki messages at the top.
Every talkpage has MediaWiki:talkpageheader at the top, which can be utilized to show various types of content in different namespaces (see e.g. hrwiki MW:Talkpageheader (shows talkpage instructions on talkpages or user notices for topic bans and similar on user talkpages, if applicable) ).
While editing an article, it is possible to define custom messages that will display at the top, e.g. MediaWiki:Editnotice-NS_number and editnotice-NS_number-article_name.
I'd like tor request the same feature for content namespaces - a mediaWiki message that would show at the top of existing pages.
It could be used to show instructions for new Draft pages automatically, to categorize all kinds of content automatically (drafts, documentation subpages, articles whose name begins a certain way), to show protection templates automatically, show messages at the top of user pages, etc.