"The packages" are the "the files describing how to go from source code to an organized filesystem hierarchy containing the useful portions of a particular piec

"The packages" are the "the files describing how to go from source code to an organized filesystem hierarchy containing the useful portions of a particular piece of software". That's the good part of nix, much like it's the good part of the Arch User Repository (AUR), and the BSD Ports system. I think the people who think the nix language is the valuable part are trying to save it, not fork it. But that's a generalization. A fork would be able to use nixpkgs even if it didn't use nix-the-language itself, with some careful planning for migration.