Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
private function writeStringRecord($stringValue)
    {
        $record = 0x0207; // Record identifier
        $data = StringHelper::UTF8toBIFF8UnicodeLong($stringValue);

        $length = strlen($data);
        $header = pack('vv', $record, $length);

        $this->append($header . $data);
    }
private function writeStringRecord($stringValue)
    {
        $record = 0x0207; // Record identifier
        $data = StringHelper::UTF8toBIFF8UnicodeLong($stringValue);

        $length = strlen($data);
        $header = pack('vv', $record, $length);

        $this->append($header . $data);
    }
Write a STRING record. This.

@param string $stringValue