Ok I do have 2 airlines off the air throttle actuator, one goes to this and the other goes to this,
The first one looks like a solenoid with a dump line & another line that looks like it goes to the front of the bus,
The other is a fitting into the transmission with 2 lines into that it also looks like the red line off the fitting into the trans goes to the front of the bus.
ALSO there's a capped off airline hanging right next to it.
It appears the capped line goes to the front of the bus also