We all know Alliance fighter squadron design:
Red Squadron
Blue Squadron
Gold Squadron (although a little hard to see)
So why was "Green Squadron" colored like this in the movie?
I will accept both in and out of universe answers, but would prefer in-universe.
And, yes, it was "Green Squadron". The pilot was Arvel Crynyd, and according to Wookieepedia:
Arvel Crynyd was a male human pilot who served in the Alliance to Restore the Republic during the Galactic Civil War. In the war's fourth year, Commander Crynyd participated in the Rebellion's attack on the Galactic Empire's second Death Star in the Battle of Endor, flying an RZ-1 A-wing interceptor in Green Squadron as leader of the squadron.