Final answer:
The routing designator and Julian Date are found on the Message Routing Information line, which is used for directing and timestamping communications.
Step-by-step explanation:
The routing designator and Julian Date are typically contained on the Message Routing Information line. This line provides critical details for the routing and handling of the message. The routing designator specifies the intended destination or distribution of the message, ensuring it reaches the correct recipients. The Julian Date, a system for representing dates, is often included to timestamp the message, aiding in tracking and coordination. These details on the Message Routing Information line are crucial for efficient and accurate communication within various systems, especially in fields like military and telecommunications where precise routing and timestamping are essential.