In a campaign game, we have 3D objects such as friendly and enemy vehicles, that move, are destroyed, etc. The positions/state of these objects are obviously written to a file, as they are restored when starting a new mission, whether the game is shut down or not (non-volatile, in other words).
As any details of which file(s) contain this data are discovered, please post your findings to this thread. Perhaps someone has already figured this out.