Developers will be required to disclose if their game uses kernel anti-cheat. This applies to both new games and existing games. Non-kernel anti-cheat is encouraged to be disclosed as well, but it’s only mandatory for developers to declare if they’re using kernel anti-cheat for the time being.
It’s worth mentioning that many games use kernel anti-cheat on windows, but only use user space anti-cheat on Steam Deck and Linux.
That’s unfortunate to hear, gamingonlinux has been a really good source for news, so I hate to hear he’s not been handling mod stuff respectably.