NZGrader needs read access to your Classroom to bring in a class, an assignment, and the work your students turned in. You will approve this on Google’s own screen.
Read-only in how NZGrader behaves: it never posts grades, comments, or files back to Classroom, and never changes a student’s work. Google’s own consent screen may describe the assignments permission as “manage” rather than “view”, since Google doesn’t offer a narrower option for it; NZGrader’s code only ever reads it. You can disconnect at any time, here or from your Google account.
Demo mode. No Google OAuth client is configured yet, so connecting loads a sample class instead of opening Google. Set GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET to run the real flow.