anchor.diff:      if (!inDiffMode()) { return '&nbsp;'; }
       const div = $('<div>', {
         'class': `diff-${cssName}-line-count`,
  -      'data-filename': diff.filename
  +      'data-filename': diffFilename(diff)
       });
       const lineCount = diff[`${cssName}_line_count`];
       div.append(nonZero(lineCount));
  
positive.code:   // - - - - - - - - - - - - - - - - - - - - - - - -
  
    const isTrueFile = (diff) => {
      const filename = diff.filename;
      return !['stdout','stderr','status'].includes(filename);
    };
  
  
negative.code:   const sortedDiffs = (diffs) => {
      let filenames = [];
      $.each(diffs, (_, diff) => {
        filenames.push(diffFilename(diff));
      });
      // ensure filenames appear in the same order as kata/edit page
      const sorted = cd.sortedFilenames(filenames);
      const diffFor = (filename) => {
        for (let i = 0; i !== diffs.length; i++) {
          if (diffFilename(diffs[i]) === filename) {
            return diffs[i];
          }
        }
  