code: protected function adjustPageBreaks(Worksheet $pSheet, $pBefore, $beforeColumnIndex, $pNumCols, $beforeRow, $pNumRows)
      {
          $aBreaks = $pSheet->getBreaks();
          ($pNumCols > 0 || $pNumRows > 0) ?
              uksort($aBreaks, ['self', 'cellReverseSort']) : uksort($aBreaks, ['self', 'cellSort']);
  
          foreach ($aBreaks as $key => $value) {
              if (self::cellAddressInDeleteRange($key, $beforeRow, $pNumRows, $beforeColumnIndex, $pNumCols)) {
                  //    If we're deleting, then clear any defined breaks that are within the range
                  //        of rows/columns that we're deleting
                  $pSheet->setBreak($key, Worksheet::BREAK_NONE);
              } else {
                  //    Otherwise update any affected breaks by inserting a new break at the appropriate point
                  //        and removing the old affected break
                  $newReference = $this->updateCellReference($key, $pBefore, $pNumCols, $pNumRows);
                  if ($key != $newReference) {
                      $pSheet->setBreak($newReference, $value)
                          ->setBreak($key, Worksheet::BREAK_NONE);
                  }
              }
          }
      }
docs: Update page breaks when inserting/deleting rows/columns.
  
  @param Worksheet $pSheet The worksheet that we're editing
  @param string $pBefore Insert/Delete before this cell address (e.g. 'A1')
  @param int $beforeColumnIndex Index number of the column we're inserting/deleting before
  @param int $pNumCols Number of columns to insert/delete (negative values indicate deletion)
  @param int $beforeRow Number of the row we're inserting/deleting before
  @param int $pNumRows Number of rows to insert/delete (negative values indicate deletion)