I know that one OAuth app has access to my Google account, because Google does not ask me to grant permissions to that app when pressing the app's log-in button. I am unable to find it in the list of apps with access to my Google account [1] though.
The app performs login using https://accounts.google.com/o/oauth2/auth with scopes 'openid email profile'.
I asked a few peers. For most of them the app does not appear in the list of authorized apps, for a few of them it does. After they revoked access and tried to log into the app again Google asked for permission and properly listed the app in the list of authorized apps again.
What can I do to revoke the app's access to my Google account?
[1] https://myaccount.google.com/permissions