the email address of the service account directly. (This is a breaking change if the numeric uniqueIDs of the Google service accounts were being used in RBAC role bindings. The behavior can be overridden by explicitly specifying the scope values as comma-separated string in the "users[*].config.scopes" field in the KUBECONFIG file.) This way, users can now  set a Google Service Account JSON key in the  GOOGLE_APPLICATION_CREDENTIALS environment variable, craft a kubeconfig file with GKE master IP+CA...