I think/hope I'm sorta understanding this.
For each of the 2 "inputs", you can select one of the following "types" of inputs:
0 - Momentary
1 - Toggle Switch (toggle up/toggle down)
2 - Toggle Switch (toggles with each contact)
3 - Garage Door
4 - Leak alarm
5 - Heat alarm
6 - Motion alert
7 - Open/close alert (door sensor)
8 - CO alarm
9 - CO2 alarm
10 - On/off report (dry contact switch/sensor)
Apparently of those 10 choices, five of them are "bound" to the relay so they don't get a separate "child" device, while the other 5 will operation totally independently of the associated relay.
I'm just not sure which 5 are bound to the relay.
My guess: 0, 1, 2, 3 are tied to the relay (the instructions state that choosing 4-10 requires you to exclude/re-include the device to create the proper child device).
However, that puts my guess off by 1 from what @bcopeland said--so, maybe he can chime in and clarify.
I'm kinda interested, because that's a lot more flexible than my current Zooz MR gizmo (where the 3 inputs and relays are locked together).