Were you referring to this: https://confluence.atlassian.com/display/DOC/Viewing+Space+Activity ?
If so, I don't think you can download the report and the features only include the followings:
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.