Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xls.php
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]);
                }
            }
        }
    }
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]);
                }
            }
        }
    }
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"