Pennywise wrote:
So, I was just curious as to why there's an extra 10 bytes with FDS at the beginning of an FDS image? I've seen it with and without and it looks mostly useless when present.
It's true that it does not contain any useful information, as the number of sides can be deduced from the file size (as can the presence or non-presence of the header).
I can't say what the historical reason was. Someone in the past decided to change it, but most emulators now seem to support both versions of the .FDS format. It seems fairly innocuous to me?