Hi there, I am the author of Extension:TabberNeue which is a forked and improved version of Extension:Tabber.
Despite I don't run a wiki on Miraheze, I would like to request the extension to be available on Miraheze.
Like most Gamepedia-authored extensions (for example Extension:DynamicPageList3), Tabber has been unmaintained for two years, and would probably stay that way after the acquisition of Gamepedia by Fandom. TabberNeue is a refactored version of Tabber that replaces Tabber completely, with full backward compatibility (aka it uses the exact same wikitext syntax so no unexpected behavior). Other than that there are multiple improvements upon Tabber, such as better accessibility support, conformation to Wikimedia UI, responsive support, and doesn't have a dependency on jQuery.
It is developed on a local 1.36 wiki and tested on our 1.35.2 production and dev wikis. If there is anything that you need from me for security review or feature requests, please let me know :)