Well, there was stow/xstow...
https://www.gnu.org/software/stow/
https://xstow.sourceforge.net/
Stow only symlinks. That's even one layer below GoboLinux, and GoboLinux is not extremely active either (it is not dead, but kind of semi-dormant, that is sometimes a few changes and improvements are added, then it goes back to hibernation again).
Stow only symlinks. That's even one layer below GoboLinux, and GoboLinux is not extremely active either (it is not dead, but kind of semi-dormant, that is sometimes a few changes and improvements are added, then it goes back to hibernation again).