Each stream and storage can have an indicator in oledump.py‘s output:

You’ll probably know M and m: they are indicators that appear often.

Here is an overview of all possible indicators:

• M: Macro (attributes and code)
• m: macro (attributes without code)
• E: Error (code that throws an error when decompressed)
• !: Unusual macro (code without attributes)
• O: object (embedded file)
• .: storage
• R: root entry