“Chimera comes with a novel userland setup based on FreeBSD core tools (replacing coreutils and related projects like findutils, diffutils, sed or grep; read our FAQ for details about why).

The FreeBSD tools were chosen for their high quality code and solid feature set. However, Chimera does not aim to replicate the FreeBSD experience on Linux in general, instead having its own choices and workflows.

The LLVM/Clang suite provides the system toolchain (clang, lld) as well as runtime parts (compiler-rt, libunwind, libc++). The C library is provided by musl, patched to use LLVM’s (also used e.g. in Android and Fuchsia) Scudo allocator for performance as well as security.

This means Chimera is not a GNU/Linux system, as it utilizes neither GNU utilities, nor GNU libc, nor GNU toolchain. However, the project is not anti-GNU/GPL, and its userland choice is primarily technical. Users are generally free to use whichever software they like.”