Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
private function writeHcenter()
    {
        $record = 0x0083; // Record identifier
        $length = 0x0002; // Bytes to follow

        $fHCenter = $this->phpSheet->getPageSetup()->getHorizontalCentered() ? 1 : 0; // Horizontal centering

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

        $this->append($header . $data);
    }
private function writeHcenter()
    {
        $record = 0x0083; // Record identifier
        $length = 0x0002; // Bytes to follow

        $fHCenter = $this->phpSheet->getPageSetup()->getHorizontalCentered() ? 1 : 0; // Horizontal centering

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

        $this->append($header . $data);
    }
Store the horizontal centering HCENTER BIFF record.