It's derived from GNUStep which was from NeXstep who Apple bought. OSX and now macOS are descendants of that design. That's where the macOS dock comes from. Not a 1 to 1 design obviously but a marriage between the operating systems thanks to Steve Jobs.
I think it’s the closest thing to that dream today.
It seems more focused on the retro aesthetic, which I personally don’t love, but it’s still really nice to see.