Often when I launch a game through Steam that “processing Vulkan shaders” window appears and loads for a couple minutes. Sometimes it takes no time, sometimes it takes several minutes. But then, for larger games like Dune Awakening or Outer Worlds 2, the game needs to sit and process shaders for another couple minutes anyway. But for some games, like Enshrouded, I can skip the Vulkan processing with no problems in the game (I do that because the Vulkan processing doesn’t go anywhere). So what is that Vulkan processing for?
The last sentence of the comment to which you replied covers this. What Valve does here is not the same thing, since it doesn’t involve the game developer or publisher, and doesn’t work for non-Steam games, and happens as an extra step. But it does come close to achieving the same effect (when it works), and it is pretty cool.
Edit: Graphics software enthusiasts who find the process interesting might want to check this out:
https://github.com/ValveSoftware/Fossilize