An updated version of the Steam Linux Runtime 4 branch was rolled out that has now shifted from Debian 11 to Debian 13 libraries for some significant upgrades. In the process more libraries have gone x86_64 only in foregoing the i386 builds. In addition, the SDL 2 library support for the Steam Runtime is now provided by sdl2-compat as the compatibility layer for SDL2 atop SDL3.
Valve and their partners at Collabora have rolled out a significant Steam Linux Runtime update to shift libraries from Debian 11 to Debian 13.2 after having skipped out on Debian 12. The approximate four year version jump has resulted in some libraries having a new SONAME for breaking ABI compatibility.
As long as they are testing proton versions, this is fine. Proton is eventually going to “do Windows” better than Windows, at the rate it’s going.
My experience so far is that it already is! Most of the titles I play (admittedly not cutting edge), I get 5-10% higher framerates running under Proton-GE on Fedora than I do natively on windows. Pretty wild to think about.