Comment by grapheneos

GrapheneOS and AOSP are Linux distributions. Linux is not glibc, systemd, GNU coreutils, GCC and GNOME. Linux doesn't have a specific libc, init system, command-line utilities, compiler toolchain, graphical environment or other userspace components. There are many Linux distributions beyond Android not using those components. There's no standard Linux userspace and a distribution using OpenRC, musl, Clang/LLVM, uutils coreutils and other software isn't somehow not Linux. Linux distribution doesn't mean systemd/GNU/Linux.

GrapheneOS and AOSP do use the userspace components developed with the Linux kernel such as iproute2. GNU components aren't part of Linux or the broader Linux project. Those don't even use a compatible license. It isn't legal to use the Linux kernel source code as a reference for writing glibc code since GPLv2-only does not permit the additional restrictions of GPLv3.