Split packages in bls12-381-gen, bls12-381, bls12-381-unix, bls12-381-js, bls12-381-js-gen. bls12-381 is a virtual package and bls12-381-unix/bls12-381-js are the actual implementation for respectively the UNIX and JavaScript versions. bls12-381-gen and bls12-381-js-gen are helpers.