wp-includes/Text/Diff/Renderer.php:188$xbeg$xlen$ybeg$ylen function _blockHeader($xbeg, $xlen, $ybeg, $ylen) { if ($xlen > 1) { $xbeg .= ',' . ($xbeg + $xlen - 1); } if ($ylen > 1) { $ybeg .= ',' . ($ybeg + $ylen - 1); } // this matches the GNU Diff behaviour if ($xlen && !$ylen) { $ybeg--; } elseif (!$xlen) { $xbeg--; } return $xbeg . ($xlen ? ($ylen ? 'c' : 'd') : 'a') . $ybeg; }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/Text/Diff/Renderer.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.