Just a point of the bomb firing button for the nav rad or visual bomb aimer; initially this was a simple bomb firing tit identical with that on WW2 bombers.
A simple wire to a small, bulb-like, housing with a protruding button. Someone twigged that this was not exactly a piece of sound engineering and it was replaced around 1965 with a flexible reinforced sheath around the cable, a substantial case, a recessed button and, I think, a metal flap that could be wire-locked shut with a tell-tale lead seal.