code: private function readLabel()
      {
          $length = self::getUInt2d($this->data, $this->pos + 2);
          $recordData = $this->readRecordData($this->data, $this->pos + 4, $length);
  
          // move stream pointer to next record
          $this->pos += 4 + $length;
  
          // offset: 0; size: 2; index to row
          $row = self::getUInt2d($recordData, 0);
  
          // offset: 2; size: 2; index to column
          $column = self::getUInt2d($recordData, 2);
          $columnString = Coordinate::stringFromColumnIndex($column + 1);
  
          // Read cell?
          if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
              // offset: 4; size: 2; XF index
              $xfIndex = self::getUInt2d($recordData, 4);
  
              // add cell value
              // todo: what if string is very long? continue record
              if ($this->version == self::XLS_BIFF8) {
                  $string = self::readUnicodeStringLong(substr($recordData, 6));
                  $value = $string['value'];
              } else {
                  $string = $this->readByteStringLong(substr($recordData, 6));
                  $value = $string['value'];
              }
              if ($this->readEmptyCells || trim($value) !== '') {
                  $cell = $this->phpSheet->getCell($columnString . ($row + 1));
                  $cell->setValueExplicit($value, DataType::TYPE_STRING);
  
                  if (!$this->readDataOnly) {
                      // add cell style
                      $cell->setXfIndex($this->mapCellXfIndex[$xfIndex]);
                  }
              }
          }
      }
docs: Read LABEL record
  This record represents a cell that contains a string. In
  BIFF8 it is usually replaced by the LABELSST record.
  Excel still uses this record, if it copies unformatted
  text cells to the clipboard.
  
  --    "OpenOffice.org's Documentation of the Microsoft
  Excel File Format"