anchor.diff:  }:
   
   let
  -  version = "3.30.2";
  +  version = "3.31";
   
     baseUrl = "https://ftp.mozilla.org/pub/mozilla.org/security/nss/releases"
       + "/NSS_${stdenv.lib.replaceStrings ["."] ["_"] version}_RTM/src";
  
positive.code: 
    src = fetchurl {
      url = "${baseUrl}/${name}.tar.gz";
      sha256Url = "${baseUrl}/SHA256SUMS";
      sha256 = "0d4a77ff26bcee79fa8afe0125e0df6ae9e798b6b36782fa29e28febf7cfce24";
    };
  
    buildInputs = [
  
negative.code: 
    passthru = {
      inherit version;
  
      srcVerification = fetchurl {
        failEarly = true;
        sha256Url = "${baseUrl}/SHA256SUMS";
        inherit (src) urls outputHash outputHashAlgo;
      };
    };
  
    meta = with stdenv.lib; {
  