So, I'm unsure of what causes the verifyAssertion REST API to return a verifiedEmail as opposed to an email. I've tried three different test accounts. All of them are registered Google accounts. However, only one of the them is a true GMail account (the others are accounts that I provided a non-gmail email address. However, I did click on the verification emails that Google sent, so they are 'verified'). Only the GMail account returns a verifiedEmail field in the JSON response. The others return an email field.
I can guess that verifiedEmail means that it's a GMail account, but since I verified the other emails, that doesn't seem totally logical.
If my guess is correct, then can I also use the presence of the 'email' to indicate that this is a verified google account, just not a GMail account?
Any insight would be appreciated.