Which ones are the official ones? There seems to be a couple which makes it a little confusing.
* GitHub Repos:
** [[https://github.com/wikimedia/WikimediaUI-Style-Guide|@wikimedia/WikimediaUI-Style-Guide]], with GitHub Pages: https://wikimedia.github.io/WikimediaUI-Style-Guide/, official url - https://design.wikimedia.org/style-guide/
* Wikimedia Cloud VPS (wmflabs.org):
** ~~<http://wikimedia-ui.wmflabs.org/>: I know this is an old site and version of the WikimediaUI, but I believe the subdomain should be a different name. With a title like that, at first it can seem like the official one. Or maybe a message at the top where it says the guide has been moved elsewhere, with a link attached.~~ (update: now shutdown)
** ~~<http://living-style-guide.wmflabs.org/>: Is this the old version which is being replaced by the GitHub Pages site, or vice versa?~~ (update: now marked deprecated)
* Toolforge:
** ~~<http://tools.wmflabs.org/styleguide/>:- Another copy of the GitHub repo.~~ (update: now redirects to <https://design.wikimedia.org/style-guide/>)
* On wiki
** ~~<https://www.mediawiki.org/wiki/Design/WikiFont>:- Will/should this documentation be moved from MediaWiki.org to the official guide, or is it to be kept on there?~~ (update: now marked historical)
** https://www.mediawiki.org/wiki/OOjs_UI
** https://www.mediawiki.org/wiki/Web_APIs_hub#Internal_resources_for_developers
* design.wikimedia.org:
** <https://design.wikimedia.org/style-guide/>
**Summary:**
**https://design.wikimedia.org/style-guide/ is the current, official style guide**, we gonna resolve this task by either deleting or clearly mark outdated resources (see sub-tasks).