Author here. This started as a hobby attempt to understand Codemasters' old driving AI, which had received quite a few interesting game reviews at the time. Which meant first reading their "BIGF" archive format. The surprise was Ruby: String#unpack is basically a fast, C-backed binary parser hiding in the stdlib, and the whole reader is dependency-free. Repo (MIT):
https://github.com/davidslv/bigfHonest note: AI-assisted throughout — I steered and verified every claim against the bytes. No game data committed; tests synthesise fixtures from the documented format.