Preserving old arcade games is a niche pastime that can involve some pretty serious hacking skills. If the story here were just that someone pulled the chip from a game, took it apart, and figured out the ROM contents, that’d be pretty good. But the real story is way stranger than that.
Apparently, a bunch of devices were sent to a lab to be reverse engineered and were somehow lost. Nearly ten years later, the devices reappeared, and another group has taken the initiative to recover their contents. The chip in question was part of a 1989 arcade game called Tatakae! Big Fighter, and it had been hacked. Literally hacked. Like with an ax or something worse.
You can read the story of how the contents were recovered. You shouldn’t try this at home without a vent hood and other safety gear. However, they did rebond wires to the device using a clever trick and no exotic equipment (assuming you have some fairly good optical microscopes and a microprobe on a lens positioner).