Two days ago, I was looking on how to get Gamescope working with a new computer on NixOS. I searched around, and found a Reddit post about it [1], found that they had a Github Gist attached to it, and then realized that I was the guy who posted it. I had completely forgot that I had done this work already.
[1] https://www.reddit.com/r/NixOS/comments/1dahr3g/steamos_base...