While I understand that Bethesda isn't likely to ever simply release the entire source code for Skyrim, I see a lot of people commenting on how the details of the Skyrim savegame file still aren't known, and that the format needs decoding. Given that Bethesda is interested in supporting modding and making their game relatively easy to mod, why is the savegame format having to be decoded at all? Why don't they simply release the format for the savegame file, possibly including the algorithm for the "save game" and "load game" functions? It seems like this would be extremely convenient for some purposes.

Is there an issue regarding copyright that I don't know about? If they release too much in the way of exact detail about their code are they somehow harming their claim to copyright?