In this specific case, nix uses fetchFromGitHub to download the source archive, which are generated by GitHub for the specified revision[1]. Arch seems to just

In this specific case, nix uses fetchFromGitHub to download the source archive, which are generated by GitHub for the specified revision[1]. Arch seems to just download the tarball from the releases page[2]. [1]: https://github.com/NixOS/nixpkgs/blob/3c2fdd0a4e6396fc310a6e86faa24d1043a8486a/pkgs/tools/inputmethods/ibus/default.nix#L63 https://github.com/NixOS/nixpkgs/blob/3c2fdd0a4e6396fc310a6e... [2]: https://gitlab.archlinux.org/archlinux/packaging/packages/ibus/-/blob/main/PKGBUILD?ref_type=heads#L16 https://gitlab.archlinux.org/archlinux/packaging/packages/ib...