Not that much actually if you don't mean as a full WM/DE replacement and instead as an on top layer; Godot 4.2 window management on linux is working quite smoothly for me, including multi-window support. From there what you do within the windows is where the magic happens. (see my other post)

What I mean is a full WM/DE replacement. I mean godot already handles graphics quite nicely. Imagine a desktop that you can control with shaders and runs on Vulkan. That'd be pretty neat.

I've thought about it but it seems daunting so I punted this idea for myself, but it depends on if you mean as an xorg/wayland replacement or if you mean to build on one of those, and even between those two they have a vastly different approach, but there are some minimal foundations that could be built on...

For example, wlroots: "Pluggable, composable, unopinionated modules for building a Wayland compositor; or about 60,000 lines of code you were going to write anyway." So it would also depend on if you mean raw WM or if you want compositing also etc.

> Just the other day I was wondering - what would it take to develop a Linux WM in Godot?

It bas been done :

https://github.com/SimulaVR/gdwlroots

But it is not up to date with Godot 4. You can have your Firefox or Blender window be a regular texture inside a full Godot game, pretty crazy...

This is sadly just a nested compositor, it seems like it does not implement any new Godot drivers…