Which campus should show up as the main one? Notre Dame? I looked at the website and Wikipedia, and I can't figure out if Notre Dame, Exchange District, or Down

Which campus should show up as the main one? Notre Dame? I looked at the website and Wikipedia, and I can't figure out if Notre Dame, Exchange District, or Downtown is the campus that should be returned. (This isn't a rhetorical question - I'd like to know the answer.)