This node creates a Google Sheets connection using interactive authentication, via pop-up.
Authentication happens in the configuration window. By default, credentials are stored in the node. Custom credentials can be set in the configuration window. A custom credential location is useful for sharing the credentials via a KNIME server or for exposing the user credentials.
After choosing the credential location, one must authenticate using the (Re-)Authentication button. A pop-up will appear that asks the user to grant access to Google Sheets and Google Drive. If you have already authenticated, the (Re-)Authentication will test the stored credentials in the selected location. When choosing and confirming the custom credentials, the default credentials will be deleted. They can be manually deleted by clicking on the "Forget Default Credentials" button.
Access can be revoked at any time by visiting myaccount.google.com/permissions
For details see: developers.google.com/analytics/resources/concepts/gaConceptsAccounts .