In short
This tool opens an Excel (.xlsx, .xls, .xlsm, .xlsb), OpenDocument (.ods) or CSV workbook without any spreadsheet software installed, to look at an attachment or find a value. Switch from one sheet to another, and search keeps only the rows that contain the text you are looking for, ignoring case and accents. Merged cells are drawn as in the file, and only the rows visible on screen are rendered, so you can browse large tables, up to 3 million cells. The values saved in the file are shown, without the formulas being recalculated. The preview is read-only: the sheet on screen can be exported to CSV, and the spreadsheet lets you edit the workbook. The file is read on your device.