It does not exist, I think it is a "degeneration" of another word, ask your friend !
What is the Machine Gambit?!

Ditto. I've heard most of the opening names, including gambit names that are not even on online lists, and I've never heard that name. My guess is that you misheard it, just as I misheard when somebody called the opening I played against the "Elfin Gambit": it turned out to be the "Elephant Gambit." Maybe you misheard "Queen's Gambit" or a mispronounced "Alekhine Gambit"?
In a real live chess tournament, my friend said something about the Machine Gambit, but what is it?!