It's the 'Mysterious Optimizer' Perk. In Fallout4 there is a perk you can unlock called: Mysterious Stranger. When you're stuck in a gunfight, this stranger has some probability of showing and assisting you.
John Carmack to help me optimize my code ... awesome!
It's based on old spaghetti westerns like Shane, Pale Rider, etc with Clint Eastwood. He's always given the title akin "Mysterious Stranger" or "Man With No Name".
