Hardware a retail hardware prototype of the Super Famicom (SNES) has surfaced on a Japanese auction site

[Krvavi Abadas]

the internals (assuming it's not just a shell with no electronic parts, the Spaceworld Gamecube hardware was a similar case.) likely aren't too different, but there's still several notable differences.
such as the red Power Switch, the expansion port being on the front of the console instead of the bottom, and a proper 3.5mm port for using the system with headphones.

considering the timing, it's likely the feature was being considered in response to the SEGA Genesis/Mega Drive having a similar port.

all that's missing to truly complete the set is the infamous "Playstation" CD-ROM attachment to go with it, the few prototypes we do have of that thing are combined units with the standard SNES components built-in.

 

[Krvavi Abadas]

for the record, it likely has nothing to do with Nintendo. and more to do with the large amount of questionably high bids it got. (notably peaking at 300,000,000 yen, or 1,932,000 dollars.)
for comparison, that Nintendo Playstation proto was sold for 360,000 dollars back in 2020.