Not working on macOS with nix

[mathmul]

It is supposedly crossplatform, yet:

nix-shell -p afetch

...
       error: Package ‘afetch-2.2.0’ in /nix/store/9rf7z9hhnxqvbf5i04labfsxill2zhyl-source/pkgs/by-name/af/afetch/package.nix:23 is not available on the requested hostPlatform:
         hostPlatform.system = "aarch64-darwin"
         package.meta.platforms = [
           "aarch64-linux"
           "armv5tel-linux"
           "armv6l-linux"
           "armv7a-linux"
           "armv7l-linux"
           "i686-linux"
           "loongarch64-linux"
           "m68k-linux"
           "microblaze-linux"
           "microblazeel-linux"
           "mips-linux"
           "mips64-linux"
           "mips64el-linux"
           "mipsel-linux"
           "powerpc-linux"
           "powerpc64-linux"
           "powerpc64le-linux"
           "riscv32-linux"
           "riscv64-linux"
           "s390-linux"
           "s390x-linux"
           "x86_64-linux"
         ]
...