Cognos download report option in URL; Updating the URL would change the report output

format=xlsxData => Use this format for Excel Data download option.

format=spreadsheetML => Use this format for Excel download option.

list of format options :

CSV,HTML,HTMLFragment,layoutDataXML,MHT,PDF,rawXML,spreadsheetML(Excel 2007 format),XHTML,xlsxData(Excel 2007 Data format), XLWA(Excel 2002 format),XML,singleXLS(deprecated), XLS(deprecated)