Well, rumors on reddit apparently from the same guy that leaked the Fallout 76 name hours before the stream went live (which is even more hours before the Bethesda stream showed anything but a table with a bobblehead on it) has leaked some more information. Don't have the actual post as I was just hearing CohhCarnage talking about it. I'm not even sure who originally leaked the name. I'd go look but have to leave soon for a Dentist's appointment.
Apparently, it's a precursor to Fallout 5. It's supposed to not be like Rust in that it's a small setting meant for a small group of people. IE - limited to 4 player co-op or something similar maybe.
Probably more stuff as when I started his stream he was in the middle of talking about some of the stuff and why he's "cautiously" optimistic.
Makes me wonder if it's more like State of Decay (except with custom building construction instead of static building construction) than Rust. IE - small scale open world survival setting, but with some side stories and possibly a main story.
Regards,
SB