> But then, how to download / extract / identify a document that is encapsulated in a requirement, except opening the xml in a text editor?
You don’t need the RTF wrapper. You can simply add any file to a rich text field. ReqIF Studio will turn it into a hyperlink, and the file will be stored in the Project folder.
You can then open the file from ReqIF Studio with your System Viewer (e.g. Excel for an embedded spreadsheet).
Have a look at this screenshot from Extend:
I hope this helps!