The Baron and Mike above me are correct. The Foot Clutch ( a heel/toe Rocker Clutch ) were in deed stock on some early model Harleys dating back as far as 1915, but the actual "suicide" clutch was a spring controlled pedal type clutch that was a custom made unit.....while stopped, and if not in neutral, if your foot slipped off the clutch, the spring return would quickly slam the pedal back and engage the clutch, causing the bike the lunge forward....hence the "suicide" name. Some of the Knuckleheads and early Panheads came stock with a hand operated shift lever on the left side of the tank, it was not possible to use a left hand operated clutch lever and shift with your left hand simultaneously, so the foot clutch was used....naturally, your right hand contorlled the throttle.
"Jockey" shifters were levers mounted directly to the shifter mechanism on the transmission below and behind the rider, shifting the bike resembled a a Horse Jockey smacking the horse with his Riding Crop.
The Mousetrap was a hand clutch, spring assisted over-center clutch release mechanism on Knuckleheads and early Panheads.
EDIT: For Baron....jockey shifter as stock???......that's a good question....I HAVE heard some people say SOME early model HD's did have a stock jockey shifter and others have said they were never stock. I have honestly never seen any stock HD with a jockey shifter. I have been to ALOT of bike shows, expos, auctions and museums, if I ever did see one, I just don't remember it. There is a very good antique HD shop near me, they have been restoring them for nearly 40 years, if anyone would know, they will....I will try to remember to call them next week and ask.