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
Edit: here’s gamingonlinux coverage of this info, includes some more information
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.
I’m not that familiar with WSL, can it interface with libraries like DirectX or Vulkan?
Me neither. I only (have to) use Windows at work, all my own PCs have been running Linux for decades…
I do know however, that WSL emulates most (but not all) Linux syscalls, so you can ran (nearly) all Linux programs on Windows - including WINE. There is also a driver in Mesa so that you can render 3D graphics from within WSL on any DX12 graphics card.