Para-Visual Display
That will be for take-off using a Para-Visual Display (PVD).
System provides a visual indication of displacement from the centreline using the localizer signal. Uses indicater stripes that move in the direction that the aircraft is required to move.
Same system is used on roll out from an auto land if ILS not cleared for automatic roll out.
System needs to be switched on, ILS manually tuned (for take off), have a valid front cse signal present, aircraft heading to be within 45 degrees of front cse, auto pilot OFF and aircraft on the ground.