Nix: Why Does My System Depend on $PKG?

Bottom Line: nix why-depends --derivation /run/current-system and nix derivation show --recursive /run/current-system are handy. NixOS and nix-darwin users – especially those following unstable – will be familiar with the situation of nixos-rebuild or darwin-rebuild failure due to breakage in a dependency. (Said user will hopefully also be grateful that this failure prevents them from switching…