> explain the possibility of a copyright violation in a piece of software written to emulate a hardware platform when there is no ROM or firmware distributed by the authors
It specifically has to do with the DRM keys used for decrypting the games; which would appear to run afoul, in most cases, of the DMCA.
It’s also not theoretical. Unauthorized DVD players and ripping software have had their authors legally prosecuted repeatedly (even big companies at the time, like RealPlayer). Gary Bowser also went to prison and had his fines set, in part, for violating that law (notice that it was a criminal case, not a civil one; Nintendo could not have dismissed those charges voluntarily.) Apple sent Psystar into bankruptcy for daring to use their keys to make macOS run on non-Macs as a commercial service. Psystar is actually the best example because they went through the entirety of the legal system to where there was nothing left but appeal to SCOTUS, and they still lost.
I think that the biggest danger to emulation, by far, which archivists should be panicking more about, is the people who emulate to avoid buying a game. Which, according to most estimates, is 90%+ of emulation. On an old console who cares? On the Nintendo Switch though, that’s actual market harm (the lack thereof being one of the pillars of determining fair use in a courtroom).