code: private function writeVcenter()
      {
          $record = 0x0084; // Record identifier
          $length = 0x0002; // Bytes to follow
  
          $fVCenter = $this->phpSheet->getPageSetup()->getVerticalCentered() ? 1 : 0; // Horizontal centering
  
          $header = pack('vv', $record, $length);
          $data = pack('v', $fVCenter);
          $this->append($header . $data);
      }
docs: Store the vertical centering VCENTER BIFF record.