glibc is under GPLv2 and I find it to be the defining piece of GNU/Linux system. The coreutils are under GPLv3 and therefore projects like Tizen use pre-GPLv3 version of such software. So parts of GNU ecosystem are popular on embedded and the others are not.
Correct. I like the phrase "GNU/Linux", but only in recent years with the popularization of other userlands that makes the distinction has become useful.
so you'd be more accurate to say just Linux, rather than parroting stallman