Valve has been Linux friendly. It says the new steam frame “is a PC” and will run Steam OS but I feel like there’s an insinuation that, like the steam deck, you can install whatever you like. I am cautiously excited at the premise of really digging in and having a Linux box strapped to my face.
Another friend has already referred to it as the Linux Vision Pro.
Edit: watching Linus tech tips review, it mentions side loading Android APKs as well
Some of the early review videos have at least implied that the same applies to the frame, but the frame itself seems to also be ARM based which may limit you a bit.