This extension isn't Wikimedia specific apart from that fact that it has Wikimedia in it's name....
The code isn't at all.... If we could have Wikidata Page Banner... I see no exception here, I mean wikidata Page Banner even looks more wikidata specific than this is.

The configs are customisable for third party installation and all that.

Default themes to display badges on Wikimedia projects

Is the description. WikidataPageBanner isn't wikimedia specific, even particularly in the name, while yes Wikidata is a Wikimedia project, I don't think of that as being Wikimedia specific because of the name, not like I do with Wikimedia Badges.

After discussing this with other members of SRE, we are willing to approve this request. However due to the number of extensions related to WikiBase that have already been requested, can you please provide an adequate descriptive reason for why you need this extension, and what you intend to do with it, if you can provide us with a sufficient reason why, we can approve this. Thanks!

There's just one job this extension does; displaying badges along side sitelinks in the sidebar of subscribed wikibase client wikis.
These badges include featured articles, good article and several others and are configurable in wikibase.php.
These badges displays alongside an article that's marked with the badge class name.

Nothing more than that.