This would presumably let x86 windows games run on ARM hardware.
This is almost certainly meant for the next Valve VR headset, but ARM has so much better power efficiency than x86 that a future ARM based Deck would be a huge improvement to battery life.
Also see this tweet:
VR games that have already secretly pushed Android ARM builds onto the Steam Store are ran via Waydroid (androidARM to LinuxARM)
VR games that do not have an ARM build on Steam (windows x86) are being translated/emulated via ProtonARM and FEX
Well, not exactly… WINE is a compatibility layer for syscalls between the x86 Windows API and (among others) the x86 Linux API, quite similar to how DXVK translates from DirectX to Vulkan.
What proton does is combine utilities like Wine and DXVK into a user friendly bundle, along with contributing substantially to the projects it bundles to make them interoperate well.
This looks to me like they want to bundle another utility, which does fast emulation of x86 user code on an ARM Linux system. Another commentator mentioned they are using FEX for this, which looks to me to do the same core task as qemu-user, but more focused on x86 to ARM and generally user-friendlier. That emulator could then be used to run x86 Wine on ARM.
The way qemu-user and FEX emulate one ISA on another is actually very cool btw. They realise massive speed gains by intercepting syscalls and executing them directly, instead of emulating a whole x86 Linux system.
by intercepting syscalls and executing them directly
Not only syscalls. FEX and Box64 also allow using native libraries instead of emulating them. That leaves basically only the game logic to be emulated.
Since Microsoft also wants x86 apps to work on their Qualcomm powered Windows laptops, can this project help Microsoft in some way?
No, not that much. The emulation of the syscalls are specific to Linux, so none of that is usable on Windows. They could reuse the emulator, but it seems likely they would write their own from scratch so they can keep everything closed source. Obligatory: fuck Microsoft.
They will likely write their own emulator, but don’t forget about WSL. You can already run WINE on Windows, I wouldn’t be surprised if you could also run FEX+WINE on Windows for ARM.
