Comment by BearOso

SNES games do have an intrinsic header that describes the cartridge content. What’s missing has to be guessed through heuristics. bsnes has a file format for describing this stuff in detail, but it’s so far not been very popular because users like things to be self-contained.

That brings up another interesting point. foone says the ROM data dumped would be identical, but that’s disingenuous. The DSP firmware is part of the cartridge, too, and it is clearly different. byuu has proposed catenating the DSP image to the base ROM for this reason. Of course, the Pilotwings case was unique, being the only game to ship with two different DSP firmwares.