final: prev: {
  # keep sources this first
  sources = prev.callPackage (import ./_sources/generated.nix) { };
  # then, call packages with `final.callPackage`

  kmscon = prev.kmscon.overrideAttrs (old: {
    version = "unstable-2022-04-28";
    src = final.sources.kmscon.src;
  });

  olympus = prev.callPackage ./olympus.nix { };

  frei = prev.buildGo118Module {
    inherit (final.sources.frei) pname version src;
    vendorSha256 = "sha256-pQpattmS9VmO3ZIQUFn66az8GSmB4IvYhTTCFn6SUmo=";
  };
}