Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Writer/Xls/Workbook.php
private function writeAllNumberFormats()
    {
        foreach ($this->numberFormats as $numberFormatIndex => $numberFormat) {
            $this->writeNumberFormat($numberFormat->getFormatCode(), $numberFormatIndex);
        }
    }
private function writeAllNumberFormats()
    {
        foreach ($this->numberFormats as $numberFormatIndex => $numberFormat) {
            $this->writeNumberFormat($numberFormat->getFormatCode(), $numberFormatIndex);
        }
    }
Store user defined numerical formats i.e. FORMAT records.