kyuusaku wrote:
As I understand it, there's a big push for SNES ROMs to be straight binary files now since copier headers are pretty useless for emulation. Strict binary in itself is stupid though since you can't always rely on the data from the Nintendo header and ROM size. Even if you can emulate most games with the header information, it won't necessarily be accurate without emulating the specific PCB the game uses.
As far as I know, all SNES emulators rely on the internal header, not the 512-byte header, to detect ROM info (although some do a better job than others). The only time I know of that an emulator will look at the 512-byte header is if a special data block (generated by the ROM tool NSRT) is present there, which provides some additional information such as controllers used, game genres, etc.
The No-Intro SNES ROM set uses .sfc for the file extension. I believe NSRT uses .sfc for headerless ROMs and .smc for ROMs with headers when renaming.