The 5 CPs from this detachment can only be spent on Stronghold Assault Stratagems.
If your army is battle-forged, all Troops units in Ork Detachments gain this ability. Such a unit that is within range of an objective Markers (as specified in the mission) controls the objective marker even if there are more enemy models within range of that objective marker. If an enemy unit within range of the same objective marker has a similar ability, then the objective marker is controlled by the player who has the most models within range of it as normal.