Yes it runs on windows, if I recall it's to pass data from storage to the GPU directly without passing through the CPU. Which lowers CPU usage and speeds up things like game loading or texture streaming for example. You probably found references to Xbox because it was implemented there first with the launch of the current gen consoles.

Yeah it's a Windows (11?) feature. AFAIK it's only supported explicitly by a handful of games, but it does appear to make a major difference for those games if the hardware used is up to the task.

It might just be a feature in the same category as "Nvidia hairFX" or w/e as a marketing gimmick though.

And linux has io_uring which can handle millions of syscalls from a single thread without breaking a sweat. In my experience, I/O on Windows is just really slow, every file operation takes 10s to 100s of times longer than on any Unix-like kernel (1000s if windows defender is enabled)