The OAuth verification FAQs state: > Ensure your app complies with the Google APIs Terms of Service, Google's API Services User Data Policy, and the Additional

The OAuth verification FAQs state: > Ensure your app complies with the Google APIs Terms of Service, Google's API Services User Data Policy, and the Additional Requirements for Specific Scopes, which includes undergoing an annual security assessment if your app accesses restricted scope Google users data from or through a third-party server. In the case of an email client data is transmitted directly from/to Google's own IMAP/SMTP servers and not a third party, and is thus exempt from the assessment.