@chjara @tomo @EeveeEuphoria Quite more that that:
- standard libc functions (sadly the syscalls aren't separated)
- fort77 (antique FORTRAN in UNIX® specification? Okay… I didn't expect that)
- Weird stuff like SCCS (Antique version-control software from 1973, CVS is almost a newborn by comparison)
- Sets the standard for the /bin/sh Shell language as well as awk, make, …
- Few device interfaces like /dev/tty and /dev/null

And probably few other things I forgot, there's really weird bits in it.