Formerly Restricted Data (FRD).

FRD is - despite the name - still classified. It is information jointly determined by DOE and DoD to relate primarily to the MILITARY utilization of atomic weapons (yields, deployment locations, stockpile quantities, weapon safety/storage) and adequately protectable as National Security Information, while retaining RD-like transmission restrictions to other countries. Like RD it is never automatically declassified; declassification requires a joint DOE+DoD determination.