this is obviously the list of directional priorities for when a pathfinder that looks for the best 4 way direction to their target is met with 2 directions that have the same distance from the target. when this happens, the pathfinder chooses the the first direction of the list (⬅️⬇️⬆️➡️) that is an eligible direction that is allowed.
defining eligibility: a direction that does not go into a wall nor go backwards (if backwards movement is prohibited)