Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Reader/Xls.php
private function loadOLE($pFilename)
    {
        // OLE reader
        $ole = new OLERead();
        // get excel data,
        $ole->read($pFilename);
        // Get workbook data: workbook stream + sheet streams
        $this->data = $ole->getStream($ole->wrkbook);
        // Get summary information data
        $this->summaryInformation = $ole->getStream($ole->summaryInformation);
        // Get additional document summary information data
        $this->documentSummaryInformation = $ole->getStream($ole->documentSummaryInformation);
    }
private function loadOLE($pFilename)
    {
        // OLE reader
        $ole = new OLERead();
        // get excel data,
        $ole->read($pFilename);
        // Get workbook data: workbook stream + sheet streams
        $this->data = $ole->getStream($ole->wrkbook);
        // Get summary information data
        $this->summaryInformation = $ole->getStream($ole->summaryInformation);
        // Get additional document summary information data
        $this->documentSummaryInformation = $ole->getStream($ole->documentSummaryInformation);
    }
Use OLE reader to extract the relevant data streams from the OLE file.

@param string $pFilename