nix-channel --list #<output> nixpkgs https://nixos.org/channels/nixpkgs-unstable The command returns a name for each channel (e.g., nixpkgs) and an URL. Note When running nix-env with the parameter -A, one can select the channel to get the package from. Such a command looks like nix-env -iA channelname.packagename.

However, it makes the “Making the package available to the user” more complex. Nix heavily relies on environment variables to make this possible