code: private function writeZoom()
      {
          // If scale is 100 we don't need to write a record
          if ($this->phpSheet->getSheetView()->getZoomScale() == 100) {
              return;
          }
  
          $record = 0x00A0; // Record identifier
          $length = 0x0004; // Bytes to follow
  
          $header = pack('vv', $record, $length);
          $data = pack('vv', $this->phpSheet->getSheetView()->getZoomScale(), 100);
          $this->append($header . $data);
      }
docs: Store the window zoom factor. This should be a reduced fraction but for
  simplicity we will store all fractions with a numerator of 100.