It's not technically a fork, it's a standalone build of vanilla LLVM (ok, there are a couple patches: https://github.com/numba/llvmlite/tree/main/conda-recipes).
> It won't even try to work with the system LLVM and insists on installing a huge wheel with custom binaries.
Not only does LLVM not have a stable ABI, it doesn't even have a stable API. It's difficult to write code that works reliably against a non-trivial number of LLVM major versions.
For the record, here is the LLVM compatibility table for llvmlite versions (llvmlite is the Python-C++ shim that Numba uses to talk to LLVM): https://llvmlite.readthedocs.io/en/latest/#llvm-compatibilit...
If you want a Numba linked against your system LLVM, the solution would be for your distribution to provide a system package for Numba (and llvmlite).