.RBJ File Extension
File TypeXRK Compiled Redcode Object File
What is an RBJ file?
File used by XRK (Extra Redcode Kit), a program that simulates battles between "warriors" that are programmed in a low-level assembly language called Redcode; stores compiled source code and is used to simulate one warrior's actions against another's in XRK.
Extra Redcode Kit is based on the Core Wars programming game, which was initially released in 1984. XRK is a complete development system that allows development, compilation, and battle simulation.