User blog comment:Brandon Rhea/Fandom and Curse Media are joining forces/@comment-1142365-20181214113202/@comment-5.172.237.249-20181214134233

"[...] And given some new features don't seem to use the MediaWiki software at all (discussions, community builder)"

You forgot Announcements and whole mobile skin - those and above uses closed-source software written in Node.js