{ stdenv, fetchurl, oxipng, lib, libarchive }: { name, manifest, ... } @ args: 
let manifestData = (builtins.fromJSON (builtins.readFile manifest)).${name};
src = fetchurl {
  url = manifestData.src;
  sha256 = manifestData.src_sha256;
};
brokenLicenses = {
  "CC BY-NC-SA 4.0" = lib.licenses.cc-by-nc-sa-20;
  "Apache 2.0" = lib.licenses.asl20;
};
fixLicense = license: brokenLicenses.${license} or license;
in
stdenv.mkDerivation ({
  inherit name src;
  nativeBuildInputs = [
    oxipng
    libarchive
  ];
  unpackPhase = ''
    bsdtar -xf $src
  '';
  buildPhase = ''
    find . -type f -name '*.png' -execdir oxipng -o max -t $NIX_BUILD_CORES {} \;
  '';
  installPhase = ''
    mkdir $out
    cp -r * $out
  '';
  meta = with lib; {
    inherit (manifestData) description homepage;
    license = fixLicense manifestData.license;
  };
} // args)