NetBSD, RedoxOS and some explicitly declines LLM contributions
rustc permits LLM code. LLVM/clang permits LLM code. GCC permits LLM use if the code itself is not LLM generated.
Yeah, good luck actually getting to run these OSes when all compilers allow LLMs in some for or another.
Edit: Mesa also allows LLM contributions. Try any usable graphics output without Mesa.