Could someone please explain why the limit is 510 bytes and not 448 bytes? Asking because I thought that the last 64 bytes were reserved for the partition table? Any link to where I can get a refresher on this topic?
Quite a few bioes only check to see if the boot signature is there, and don't bother validating the partition table, so effectively you can use those bytes if you don't care about compatibility.
Not an expert but since they didn't plan on actually booting an OS, perhaps they didn't need the partition table so those 64 bytes could go toward more instructions for solitaire.
Wikipedia has a good article to dust the memory off: https://en.wikipedia.org/wiki/Master_boot_record