{ config, pkgs, ... }:
let
  unstableTarball = fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixos-unstable.tar.gz;
in
{
  nixpkgs.config = {
    packageOverrides = pkgs: {
      unstable = import unstableTarball {
        config = config.nixpkgs.config;
      };
    };
  };
  virtualisation.virtualbox.host = {
    enable = true;
    enableExtensionPack = true;
  };
}