Probably a stupid question. I was looking at the black/white version. Reminds me of an Orca. Which in turn raised a thought. Fish have a dorsal fin. Turns out that some fighter jets do as well.
From what I read, increases side slip angle" and "At high side slip angles, it produces stable vortices along the surface of the vertical tail which produces higher suction force over vertical tail, thus increasing the side force." (not a huge one)
Ok. I dont understand all that. Sounds good though. More stable, increase increase cooling surface area, and house some electronics. But it would add to cost, and people would probably not like the looks of the fin.