An electronic security key, color coded yellow.”
An electronic security key, color coded yellow.
This item can be found on the body of a dead Enclave guard at the vertibird crash site in Klamath. It would seem that the Chosen One could use the keycard to open the respective yellow security level doors in the Gecko's nuclear power plant reactor, but it doesn't actually open anything. Instead, proper keycards can be found from around the plant.