ods

Three ODS files: ods_1_sheet (5.8 KB), ods_3_sheets (5.9 KB) and ods_100_rows (7.6 KB). ODS is the OpenDocument spreadsheet format used by LibreOffice Calc, and it is a zip of XML like XLSX but with a different layout, so Excel-focused tools often cannot open it. Use these files to test that your site accepts .ods, that an importer reads the first sheet or all three correctly, and that the 100 row version loads fully. The multi-sheet file is the useful one for checking that your code does not read only the first tab by accident.