|The following is based on Fallout 76 cut content and has not been confirmed by canon sources.|
The vault's original purpose in the vault experiment is unknown. The vault is powered by four generators, similar in design to the generators found in Vaults 51 and 94.
Though it is not possible to explore the vault, the game files reveal much about the internal layout. Within the vault cell appears to be a cave. The vault door stands vertically and is met with an extended catwalk. At the entrance are several radiation scanners. The vault is set up with 31 spawn points for feral ghouls and one glowing one.
The vault is expansive with three elevators. Inside the vault, there are two default terminals without any entries, a chemistry station, and a cooking station. In addition to the sections listed below, the vault has a utility center with industrial machinery that also appears throughout Appalachia. Sections in the vault include:
- Exit zone
- Overseer's office
A "vault trunk" for Vault 65 exists alongside trunks for Vault 63, 76, 94 and 96. Vault 65 is the only one of these that does not exist in-game. Within the game files, Vault 65 is also referred to as "Vault 75." Coupled with the 11/30/2017 date stamp on the cell for Vault 65, this may have been a prototype for Vault 76 or one of the other vaults in the region.