I couldn't find a "wiki" focused repo, I hope this is the right place.
I'm looking here https://wiki.manjaro.org/index.php/Installation_Guides
Under the title Manjaro Installation Guides
, there is a link to https://manjaro.org/support/userguide/ , which returns a 404 and redirects to https://manjaro.org/?404
I'm not actually sure of what the correct link is, I'm just getting starting with Manjaro.