From the ptr notes Link:

Macro Changes
Symbol "@" added as a synonym for "target=". For example: "/cast [@focus] Flash Heal".
New macro conditionals: "vehicleui" (if the player has a vehicle UI) and "unithasvehicleui" (if the target of the macro has a vehicle UI).
The new target synonym is going to be damn useful, will shorten FTL macros considerably.

I'm interested in how exactly 'vehicleui' will function. Can we set up generic /cast [vehicleui] VehicleAbility1, or is it more for /leave vehicle command type macros.

Also, I have no idea how 'unithasvehicleui' can be used.