{
  pkgs,
  lib,
  inputs,
  ...
}:
{
  nix.settings.experimental-features = [
    "nix-command"
    "flakes"
  ];
  # ExplanationNote: disable global registry
  # to keep only system registry.
  nix.settings.flake-registry = "/etc/nix/registry.json";
  #nix.registry.self.flake = inputs.self;
  nixpkgs.flake = {
    # ExplanationNote: use input.nixpkgs to record a public rev
    # into flake.nix using flake:nixpkgs as an input.
    source = inputs.nixpkgs;
    #source = pkgs.path;
    setNixPath = true;
    setFlakeRegistry = true;
  };
  nix.registry.nixpkgs = {
    from = {
      id = "nixpkgs";
      type = "indirect";
    };
    to = {
      owner = "NixOS";
      repo = "nixpkgs";
      inherit (inputs.nixpkgs) rev;
      # May be overriden by nixos/modules/installer/cd-dvd/channel.nix
      type = lib.mkDefault "github";
    };
  };
}