I'm puzzled as to what it could be, assuming it's not a mistake. Bethesda and Microsoft do have a cosy relationship dating back to the original Xbox and Morrowind. It's worth noting that Fallout 76 has no platforms listed. Or there could be some unforseen surprise exclusive they've wrangled. I could see Bethesda and MS agreeing on a remaster of one of their older games, for instance.