File from https://www.rondebruin.nl/win/s2/win003.htm. I have been in conversation with the author, who has no objection to its use. I have not actually opened the file in Excel (at least not with macros enabled); I am using it merely to demonstrate that the ribbon data is read and written correctly. Test added; no source code changed. This should slightly increase coverage for Reader/Xlsx (moderate), Writer/Xlsx (slight), and Spreadsheet (substantial). Note that this file has no Ribbon Bin objects, so some coverage is still lacking.
oleibman