code: function fileNameFilter(includesLastSegment, rangeText) {
              if (includesLastSegment) {
                  var rightmostSlash = rangeText.lastIndexOf('/');
                  return rangeText.substring(rightmostSlash + 1);  // safe even if rightmostSlash is -1
              } else {
                  return "";
              }
          }
docs: For main label, we just want filename: drop most of the string