anti-roll-out

Mechanical System Functional Test
Open the cargo compartment door and verify that the PFW Aerospace AG CLS has been installed in accordance with PFW installation drawing BX900023.
1) Lower the door sill protector (if applicable) and raise the anti-roll-out
2) Check all cargo Locks to ensure they are in the retracted position
3) Check all cargo Latches to ensure they are in the right position for XX.Y"
wide ULDs
4) Orient the loaded test ULD for position E outside the aircraft,
XX.Y" laterally anti-roll-out


So can any one tell me what is "anti-roll-out"?