This is a Wehrmacht ability. Though this might be one of the least flashy abilities found in the game, it should not be underestimated by any means. It is a passive ability that doesn't cost you any resources, and thus you don't have to remember to activate it at the right moment. Flanks from incoming enemy squads will be spotted much earlier, which helps you react to enemy movements properly and reposition your units. This is especially useful for your MG42s - you can adjust their cone of fire to counter your opponent's flanking maneuver.