self: super: {
  cgit = self.callPackage ./cgit { inherit (super) cgit; };

  dino = self.callPackage ./dino { inherit (super) dino; };

  emacs-overlay = self.extend (import ./emacs/overlay);

  inherit (self.emacs-overlay) emacsPgtk;

  emacsPackagesFor = emacs: self.callPackage ./emacs/packages.nix {
    emacsPackages = super.emacsPackagesFor emacs;
  };

  firefoxPackages = self.callPackage ./firefox/packages.nix {
    inherit (super) firefoxPackages;
    llvmPackages = self.llvmPackages_latest;
  };

  gnupg = self.callPackage ./gnupg { inherit (super) gnupg; };

  public-inbox = self.callPackage ./public-inbox {
    inherit (super) public-inbox;
  };

  python3 = self.callPackage ./python { python = super.python3; };

  thunderbird = self.callPackage ./thunderbird {
    inherit (super) thunderbird;
    llvmPackages = self.llvmPackages_8;
  };
  thunderbird-68 = self.callPackage ./thunderbird {
    thunderbird = super.thunderbird-68;
    llvmPackages = self.llvmPackages_latest;
  };

  tmux = self.callPackage ./tmux { inherit (super) tmux; };

  youtube-dl = self.callPackage ./youtube-dl { inherit (super) youtube-dl; };
}