Question: The Northrop F-15 Reporter was based on a night fighter that included how many mounted M2 Browning machine guns?
Sentence (from "Northrop P-61 Black Widow"): It was armed with four 20 mm (.79 in) Hispano M2 forward-firing cannons mounted in the lower fuselage, and four .50 in (12.7 mm) M2 Browning machine guns mounted in a remote-controlled dorsal gun turret.
Relevant evidence: Yes