AFAIK Clang (not LLVM) was entirely created by Apple and could have been proprietary Also the x86 Darwin kernel was made open source with no benefit to Apple,

AFAIK Clang (not LLVM) was entirely created by Apple and could have been proprietary Also the x86 Darwin kernel was made open source with no benefit to Apple, and winocm managed to port it to ARM too (although it's pretty debatable if it actually provides anything useful)