McDonald's Filet-O-Fish sandwich is delicious, but what's actually in it?

I expected some kind of Frankenfish. But really, the Filet-O-Fish is made with Alaskan Pollock, a whitefish

Surprisingly, the Filet-O-Fish even has an MSC Sustainable Seafood certification

Beyond that, there's cheese, a bit of tartar sauce, and a bun. Swipe up for the full breakdown, and nutrition data.