Valve’s Proton software makes it possible to play many Windows PC games on computers running Linux-based operating system, including Valve’s own Steam Deck handheld gaming PC. So far Proton has only been available for PCs with Intel or AMD processors based on x86_64 architecture,

Valve are likely up to something hardware-related again, report NotebookCheck. Their next chunk of plastic and wires – following the Valve Index, Steam Deck and Steam Deck OLED – could swap PC gaming’s favoured x86 architecture for ARM, the type of processor favoured by the Nintendo Switch, Macs, and mobile phones.

Proton is Valve's solution for running many Windows games seamlessly on the Linux-based SteamOS. The leaked code shows Valve testing this ARM64 version with a wide

It looks like Valve is working on bringing the Steam Deck's "special sauce" for Windows games on Linux to Snapdragon and other ARM devices.

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,

Valve is working on an ARM64 implementation to bring x86-based Steam titles to mobile devices — including its rumored standalone VR headset

Valve appear to have some pretty ambitious future plans for Steam, as we've seen recently a leak (and not for the first time) that Valve has plans for ARM64 and Android support on Linux.

Valve may be developing an ARM64 version of Proton for Linux gaming. Hundreds of games, like Left 4 Dead, have been tested for compatibility using a new 64-bit layer. The potential for ARM64-based portable consoles opens exciting new possibilities.