Can someone please explain how different topics in a uORB message works?

In actuator_controls.msg, there are several topics such as “actuator_controls_virtual_fw”, “actuator_controls”, “actuator_controls_0”, “actuator_controls_1”, etc. These are all used in different ways in the fixed wing attitude control module.

How do I know when to use which?

I could not find descriptions of these in the documentation (