Seen on Reddit, a prototype in a state very close to the final version. It is a motherboard of the Macintosh LC.
The conversations under the post are interesting, but basically, the machine has no markings (he didn’t include photos), and the chips for the ROM are EEPROMs (programmable) and not ROMs (which cannot be modified). You can also see that the chips are labeled FC (for Final Candidate?) and that there is a red button in the middle. It’s not uncommon on production machines (even though it is not widespread) and is used here to perform a PRAM reset.
