GoboLinux had nice ideas, but to me it feels like nix (and guix) have superseded it.
I don’t know, their approach of union mounts sounds to me like a better way to achieve what Nix does with symbolic linking.
GoboLinux’s filesystem reminds me superficially of macOS, at least the way that the macOS filesystem is presented to regular users with “Macintosh HD” containing
Now that I consider it, macOS is a bit of a half-assed Frankenstein[‘s monster] of this idea. I’m glad to see someone’s committed to whole-assing it.