anchor.diff:  
     src = fetchurl {
       url = "mirror://sourceforge/flightgear/release-${shortVersion}/${pname}-${version}.tar.bz2";
  -    sha256 = "XXDqhZ9nR+FwQ3LauZe8iGxOjlyDXDrEtj61BQGVDYc=";
  +    sha256 = "sha256-/icGx3B+pzq8URR3PeRfKYYasPj1NWVq8EKO0EnKSpc=";
     };
   
     # Of all the files in the source and data archives, there doesn't seem to be
  
positive.code: }:
  
  let
    version = "2020.3.8";
    shortVersion = builtins.substring 0 6 version;
    data = stdenv.mkDerivation rec {
      pname = "flightgear-data";
  
negative.code: 
      src = fetchurl {
        url = "mirror://sourceforge/flightgear/release-${shortVersion}/FlightGear-${version}-data.txz";
        sha256 = "sha256-Ej8VGywPQiDw3VXodcpXpOw4qU9x+MBMWMrqwHfitVg=";
      };
  
      dontUnpack = true;
  