pass NEXTCLOUD_VERSIONS the command line instead

I've recently tried to improve my nextcloud setup (including a full reinstall, here are some notes https://discourse.nixos.org/t/how-to-get-beyond-the-current-nextcloud-module/30533/3). I was looking at patching https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/nextcloud/packages/generate.sh (to be able to run it from any directory) and was confused by the NEXTCLOUD_VERSIONS variable that did not seem to be used ? Is there a way to pass the nextcloud version on the CLI instead so that it's more explicit ? Also I wonder if you had considered moving the repo to https://github.com/nix-community/ ? many *2nix programs live there to ease contributing/discovery. Also would be nice to have a `--help` available, if only to discover how to use the program.