This parameter specifies a refresh token for OAuth 2.0 authentication to a specific Google account.
If you already know the token, you can copy/paste it into this parameter. To obtain a new token, click the browse button. This will prompt for a Google account authentication page from Google.
It is recommended that you save the defaults (from the Defaults button on the dialog) once the refresh token is retrieved so you will not have to re-authenticate in the future.