XIGNCODE3 is another popular anti-cheat like Easy Anti-Cheat and BattlEye that currently causes issues for Linux and it's going to hopefully see support (thanks Reddit) for Linux and the Steam Deck by launch.
Developed by Wellbia, XIGNCODE3 protects something around 272 titles according to their website although that appears to be spread across PC, mobile and consoles.
What games specifically use XIGNCODE3? That's actually not all that easy to find out, as Wellbia don't list the games specifically. Black Desert Online did previously use it but that switched over to Easy Anti-Cheat. Games that do use XIGNCODE3 that we've been able to find include Aion, Blade & Soul, DJMAX RESPECT V, Knight Online and the upcoming ELYON.
It's not exactly surprising to suddenly see more vendors look to support Linux either through native builds or Proton, since we know the Steam Deck has a lot of excitement around it. Since it uses SteamOS 3 (based on Arch Linux), any anti-cheat will likely need to be updated for it.
We've sent off a message to Wellbia to see if we can find out more information.