This patch lets players be able to move any unit under their control around. Cf. this thread.
One can set "Controllable" to false for an entity in the new Controllability component to prevent this behaviour for that unit.
The check whether a unit can be controlled is moved higher up the command-chain, which seems more logical to me.
When the Control all units-cheat is on, an entity can still be controlled.
Also the check whether one can delete an entity is moved to this component.