@leyonhjelm Software doesn't have a "foundation" like a building, as it doesn't face physical limitations - you can build the software equivalent of a huge castle built only on top of a single instruction.

systemd is arguably more of a "foundation" than Linux, as Linux will panic() on boot and shut down if it can't find systemd; https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/init/main.c#n1525


The real foundation is the solid bedrock of all the GNU code that every nontrivial piece of free software and even nonfree software relies on.