This could have been a great source of information: https://www.latexwiki.com
It does seem to be neglected these days, with much information wrong. It does not seem possible to register with the site to do additions and corrections, as you just get an error because you are not an administrator, so maybe it’s just been abandoned?
Anyone know??
Site seems to have been abandoned some years ago. The material on it is mostly out-of-date and creating an account seems impossible.