Thats the handbrake cable return spring the black plastic piece has snapped, it screws onto the threaded end of the cable adjuster underneath the van. Easy fix, i believe the black plastic part is common to t4, t5, t6 and should be readily available. In interim you can likely repair with cable ties.https://campervanculture.com/shop/handbrake-cable-tension-spring-t5-03-15-t6-16/