"The output executable is byte-for-byte identical with said release, which means that the source code accurately represents the original engine's behavior."
That seems crazy that someone could reverse engineer compiled code back into the higher level language it came from, and then have that code compile into the exact same executable. Obviously, you can keep modifying the code until it matches, but it's still impressive for anything other than a small program.
I just watched a documentary about how Super Mario 64, a game for Nintendo consoles, was reverse engineered in a way that will also generate byte-identical objects when being compiled. I found this nothing short of amazing. This is the link to the part of the video that mentions this: https://youtu.be/NKlbE2eROC0?t=206
That seems crazy that someone could reverse engineer compiled code back into the higher level language it came from, and then have that code compile into the exact same executable. Obviously, you can keep modifying the code until it matches, but it's still impressive for anything other than a small program.