It's a "disassembly", so it's the work of somebody converting machine code back into assembler, and studying it long and hard to add comments, break out numbers into sensible-named constants, and choose decent names for loop labels. The original dev team was almost certainly not involved.
Thanks for the clarification. Given what you've said and the size of the thing, this is an awesome piece of work. The level of detail and perseverance required is enormously impressive.
