Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
private function writeAutoFilterInfo()
    {
        $record = 0x009D; // Record identifier
        $length = 0x0002; // Bytes to follow

        $rangeBounds = Coordinate::rangeBoundaries($this->phpSheet->getAutoFilter()->getRange());
        $iNumFilters = 1 + $rangeBounds[1][0] - $rangeBounds[0][0];

        $header = pack('vv', $record, $length);
        $data = pack('v', $iNumFilters);
        $this->append($header . $data);
    }
private function writeAutoFilterInfo()
    {
        $record = 0x009D; // Record identifier
        $length = 0x0002; // Bytes to follow

        $rangeBounds = Coordinate::rangeBoundaries($this->phpSheet->getAutoFilter()->getRange());
        $iNumFilters = 1 + $rangeBounds[1][0] - $rangeBounds[0][0];

        $header = pack('vv', $record, $length);
        $data = pack('v', $iNumFilters);
        $this->append($header . $data);
    }
Write the AUTOFILTERINFO BIFF record. This is used to configure the number of autofilter select used in the sheet.