The Linux Documentation Project has been around for 20+ years: https://tldp.org/ Its history is here: https://tldp.org/history.html It is not obvious to me if the two projects have different goals.
Is tldp still being maintained ? Last update seems to have been in 2020 based upon the main page. I wish GNU and Linux took a page from OpenBSD, if a command is changed, a man page is created that contains all information we need. Instead we have many sources of information, all with different info.
The one true source of man pages on Linux: