c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
          ‘nextcloud-27.1.11’ to `permittedInsecurePackages` in
          ~/.config/nixpkgs/config.nix, like so:

            {
              permittedInsecurePackages = [
                "nextcloud-27.1.11"
              ];
            }