The default VPA: this is the VPA that will be invoked when the "Push-To-Talk" button is pressed. An empty value indicates that no VPA will be invoked (the "Push-To-Talk" button is disabled).
Privacy mode for VPAs. When enabled, the user cannot invoke VPAs and VPAs will not proactively start a conversation or send any notifications to the user. This can be used in restricted modes such as valet or for guest drivers.