https://www.cnet.com/news/the-fallout-76-beta-will-feature-the-entire-game/

In video game land, beta tests usually give players access to a restricted area of an upcoming game. A small taster to test online servers or game balancing.

If Bethesda has its way, the Fallout 76 beta will give players access to the entire game. And here's the kicker: Progress made in the beta will transfer over to the final game.