Gamepedia is using a 1.0.0-hydra version, which is seemingly closed-source and used exclusively on their sites. Note that this is no violation of license terms, as this extension is using ISC instead of GPL.
If they are interested, they should benefit from the new features introduced in the genuine version of the extension (like working with MW 1.32+, better maintainability, tracking categories, etc.), but possible improvements and bugfixes from their side are of interest as well. Ideally, both projects could merge into one at some point.
Maybe, this can even lead to get them invested into public MediaWiki extension development as well.