But what a weird, "stepped" leading edge. What would be the (aerodynamic) advantage of that, do you suppose?
Aerodynamically I would suggest it's perhaps to take advantage of the stagnated airflow (high pressure) in front of the airfoil, Mosquito, certain models of the Fairey Firefly used a similar configuration. The F4U Corsair used the same position for engine supercharger intake, intercooler and oil cooler air.
Some light reading.
http://naca.central.cranfield.ac.uk/...report-743.pdf