The MissionTriggerPortPos is a ready to go prefab of a SCR_Position entity (with a hierarchy component pre-attached).
This prefab can be placed anywhere in the world where you would like to teleport players with a MissionTrigger.
Once placed and rotated, it simply needs to be made a child entity of the MissionTrigger that you wish to use.
If several of these prefabs are placed as a child of a MissionTrigger, the teleport destination will be random choosen by one of the positions.
With the exception of its origin and rotation settings,
it has no options to configure and will only be visible inside of the WorkBench.