Once the TIBCO Spotfire connector for Google Analytics has been setup to work with the TIBCO Spotfire Web Player has been setup i.e after you create the OAuth credentials for Spotfire in your Google project (see
Configuring the Google Analytics connector for more details), the generated ClientID (public identifier for the application) is used to authenticate the user and allows user to access data. So when Google Analytics is selected on the Web Player, it redirects to:
https://accounts.google.com/signin/oauth/oauthchooseaccount?client_id='ID_set_in_preferences'.........
Then Google gives access to all data or Google accounts that the user have access to, even though the ClientID and ClientSecret are part of or generated in a particular Google account or project.