Depends how hairy the code is really. Any format can be reverse engineered, but that doesn't make it open. Is it really open if the code is so hard to read it's

Depends how hairy the code is really. Any format can be reverse engineered, but that doesn't make it open. Is it really open if the code is so hard to read it's not much easier than reverse engineering from a compiled program? I don't actually know anything about The GIMP's format, just talking in general.