Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
private function writeGridset()
    {
        $record = 0x0082; // Record identifier
        $length = 0x0002; // Bytes to follow

        $fGridSet = !$this->phpSheet->getPrintGridlines(); // Boolean flag

        $header = pack('vv', $record, $length);
        $data = pack('v', $fGridSet);
        $this->append($header . $data);
    }
private function writeGridset()
    {
        $record = 0x0082; // Record identifier
        $length = 0x0002; // Bytes to follow

        $fGridSet = !$this->phpSheet->getPrintGridlines(); // Boolean flag

        $header = pack('vv', $record, $length);
        $data = pack('v', $fGridSet);
        $this->append($header . $data);
    }
Write the GRIDSET BIFF record. Must be used in conjunction with the
PRINTGRIDLINES record.