They took their sweet time but both the project lead Ryan Houdek as well as Valve developer Pierre-Loup Griffais (username Plagman here in the comments) have now come out saying that FEX-Emu was not just sponsored by Valve but is actually their project and that they approached suitable developers with the idea who they have been paying for the development: https://www.gamingonlinux.com/2025/12/valve-have-been-fundin...

https://gamersnexus.net/pc-builds-news/valve-steam-machine-d... "Valve has devoted significant resources to the development of FEX emulation."

Man, Fex is Valve, Valve is Fex! The steam logo is right there in the logo!

https://files.mastodon.social/accounts/headers/110/652/595/6...

Center of left side, it is a Valve product. All main devs are employed by Valve.

As the random commenter I agree. By "support" I meant that they have a line of product and a strategy that relies on FEX to work and work as seamlessly as possible.

If they contribute to FEX at even a fraction of what they did to wine and Proton it is indeed huge.