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
It is impressive how far those emulators have come, especially since they got the option to use native libraries instead of emulated ones, but the game logic itself will always need emulation…
This doesn’t mean it can’t be done, it just means that the ARM CPU needs to be pretty fast to counter the emulation overhead, and that’s why I have my doubts about the energy efficiency…
(Btw: I have tried running several AMD64 games on my A311D powered MNT Reform laptop with Box64. It’s impressive how well the emulation runs, and how many games are actually playable already. However, I also encountered a lot of games that don’t reach enjoyable FPS on that hardware. With a faster ARM chip though…)
With a big dev like valve backing it they could probably implement a pretty impressive JIT/cacheing scheme - of course nothing beats native but this gap will close over time