File Types in Excel: When to use XLSX, XLSM, XLSB, XLS etc.?
XLSB File Extension - What is an .xlsb file and how do I open it?
XLSX or XLSB: Why to save a workbook in binary format
Extensions of Excel File – File Formats Supported in Excel - Earn & Excel
Reverse Engineering and More on Twitter: "RE tip of the day: In OOXML files, if macros are supported, the last letter of the file extension will be m rather than x (example: .