NixOS is organized into modules, as are a few community projects modeled after it, like Nix-Darwin and Home Manager. A more unified module system could mean

NixOS is organized into modules, as are a few community projects modeled after it, like Nix-Darwin and Home Manager. A more unified module system could mean * NixOS supporting kernels other than Linux * NixOS supporting init systems other than systemd * NixOS supporting usermode services (i.e., code sharing between Home Manager modulea and NixOS modules) * NixOS supporting a 'guest mode' for configuring system services (i.e., NixOS foldinf in Nix-Darwin and supporting similar systemwide service configuration on other foreign operating systems). In this case, I'm talking mainly about the first, as a starting point, and hinting at the others.