There's a chance you could have been invited to the closed beta of Fallout 4's Creation Kit.
Fallout 4: Bethesda opens sign-ups for Creation Kit closed beta before shutting it down
Alongside Fallout 4's Survival Mode, Bethesda is also working on the game's Creation Kit, the all-in-one modding suite that's going to really expand the horizon of what's possible for mods.
This kit is still a ways of, however, as it's currently being tested in a private beta, but Bethesda seems ready to invite more players. In a post on the official forums, which has since been removed, Bethesda revealed some details as to how players can enter into the closed beta.
According to Polygon, entrants needed to also sign up for the DLC beta, as well as accept a non-disclosure agreement.
It's not clear at this stage whether the post's removal was due to increased demand, or if it was simply not supposed to be revealed this early.
We'll let you know if it reappears.