==IDKFA== 

 The meaning of this is unclear.  It is variously described as 
 ID Kicks Fucking Ass, or ID Killer Full Ammo.  I went back 
 to the original Doom source ftp://ftp.idsoftware.com/idstuff/source/doomsrc.zip 
 to see if I could resolve this.  Indeed the comments in st_stuff.c 
 give definitions for these cheat codes: 

 IDFA is commented as: 

  // 'fa' cheat for killer fucking arsenal 

 IDKFA on the other hand is commented as: 

  // 'kfa' cheat for key full ammo 

 So it looks like "ID Kicks Fucking Ass" is apocryphal. 

 

 == MOTHERFUCKENKIWIBASTARD == 

 Why do people keep removing MOTHERFUCKENKIWIBASTARD? It is a real cheat code, I have tested it myself. —  |   
 :Yeah, it's real, and famous among Amiga users. Definitely should stay.