the sgnl://linkdevice uri provided (typically in qr code form) by the new device
Example: "sgnl://linkdevice?uuid=jAaZ5lxLfh7zVw5WELd6-Q&pub_key=BfFbjSwmAgpVJBXUdfmSgf61eX3a%2Bq9AoxAVpl1HUap9"