anchor.diff:    coreutils,
     docker,
     e2fsprogs,
  +  fakeroot,
     findutils,
     go,
     jq,
  
positive.code:         name = "${baseName}-customisation-layer";
          paths = contentsList;
          inherit extraCommands;
          postBuild = ''
            mv $out old_out
            (cd old_out; eval "$extraCommands" )
  
            mkdir $out
  
            tar \
              --sort name \
              --owner 0 --group 0 --mtime "@$SOURCE_DATE_EPOCH" \
              --hard-dereference \
              -C old_out \
              -cf $out/layer.tar .
  
            sha256sum $out/layer.tar \
              | cut -f 1 -d ' ' \
  
negative.code:     created ? "1970-01-01T00:00:01Z",
      # Optional bash script to run on the files prior to fixturizing the layer.
      extraCommands ? "",
      # Optional bash script to run inside fakeroot environment.
      # Could be used for changing ownership of files in customisation layer.
      fakeRootCommands ? "",
      # We pick 100 to ensure there is plenty of room for extension. I
      # believe the actual maximum is 128.
      maxLayers ? 100
  