On September 20, Valve pushed changes to a test application visible on SteamDB indicating a massive list of games being tested with its Proton compatibility layer. Interestingly, there now also seems to be an ARM64 version of Proton, which exists to make Windows games playable on Linux. This version of Proton, "proton-arm64ec-4", is listed as being tested with literal hundreds of games, but popular titles like Left 4 Dead 2 and Shadows of Mordor stick out here, showing a wide range of possibilities with ARM64 Proton behind the scenes.
Now, what does all of this mean? While Valve has yet to make any kind of official announcement regarding ARM64 support on SteamOS, or for Proton, it clearly seems to be a priority and part of its push for gaming on Linux, in general. Now, though, Valve seems to want to expand its Linux gaming audience from just x86 hardware, and start folding in Linux Arm devices in line with ongoing efforts to improve gaming on Windows for Arm. There are also some mentions of Waydroid, which means even Android Arm devices may be getting Proton support, which would surely expand its audience significantly.
