This is what happens when a trace gets hit with high voltage. It vaporizes off of the PCB. The wires are just jumpers to repair those zapped traces. Nothing wrong with repairing bad traces with jumper wires. It is better that scraping a board because of it. Granted it is working, leave it be and live with it. It shouldn't cause issues unless it was done wrong to begin with. Whomever did the repair did not bother to clean up the carbon built-up though, so it looks messy. If you want with the game off and the board out of the machine, grab some q-tips and rubbing alcohol and clean up those areas that are covered in soot.