Comment by ericbarrett

Most games don’t store their assets in a single one-shot-load pack file anymore. They use chunked asset files where individual assets or packs will be compressed and then concatenated with a master index, meaning you don’t have to load the whole file when the engine needs only a subset. This means the checksums necessarily cannot cover the entire data file, because then you would need to read the entire file to verify a single asset anyway, throwing away the benefits of random access. You can also turn the checksums off for “speed,” and some do.