It is handy to know how much space is left in a cargo auton. The Jettison screen will show this. But if the player has no items in the cargo hold when selecting the Jettison action they see a "There are no items in your cargo hold that can be jettisoned" screen which doesn't show the remaining auton cargo space.
The playership cargo hold can frequently be empty when the player is moving items between multiple autons, crates or abandoned stations and the player is then unable to check the amount of cargo space left in the auton, unless they grab some item to allow them to check.

The "Main" dockscreen already shows "You are docked with a 330M mule auton".
Suggest that it also show the available cargo space for the auton so it can always be checked by the player.

With the addition of the cargo auton attribute it may be worthwhile making the mule dockscreen a separate cargo auton dockscreen. This would allow mod cargo autons to access it.