Yes I know, the gurney is the endplate effectively that keeps the airflow attached. I was shocked by this as F1 cars first had wings with no gurneys, so how could this 50s thing come about when Dan Gurney invented them?
Wiki said he took the concept to F1 and modified it for front and rear wings.
"....recalled experiments conducted in the 1950s by certain racing teams with "spoilers" affixed to the rear of the bodywork to cancel lift. (At that level of development, the spoilers were not thought of as potential performance enhancers—merely devices to cancel out destabilizing and potentially deadly aerodynamic lift.) Gurney decided to try adding a "spoiler" to the trailing edge of the rear wing.[8] The device was fabricated and fitted in under an hour, but Unser's test laps with the modified wing turned in equally poor times. When Unser was able to speak to Gurney in confidence, he disclosed that the lap times with the new wing were slowed because it was now producing so much downforce that the car was understeering. All that was needed was to balance this by adding additional downforce in front.[9]
Unser realized the value of this breakthrough immediately and wanted to conceal it from the competition, including his brother Al. Not wanting to call attention to the devices, Gurney left them out in the open.[10] To conceal his true intent, Gurney deceived inquisitive competitors by telling them the blunted trailing edge was intended to prevent injury and damage when pushing the car by hand. Some copied the design, and some of them even “improved” it by pointing the flap downwards, which actually hurt performance.[11]"