I love the smell of UnrealEd crashing in the morning. – tarquin
Legacy:QuakeC
From Unreal Wiki, The Unreal Engine Documentation Site
QuakeC is a C-like language to code the Quake Virtual Machine, like UnrealScript is for the Unreal engine.
The compiler (frikqcc, qccwin32, ...) generate a "progs.dat" file that is load with the following parameter and changes the gamelogic of quake.
-game <folder where is the mod>