My guess is that it's been modified for use in an arcade machine - those cables would have plugged into an adapter board that connected to the machine harness.
I would agree with this. Two of the cables are probably wired to allow the connection of JAMMA controls, while the 3rd is probably used for video and power? Most of these console/arcade kits worked on a timer, where your money simply purchased you a specific amount of time to play before the controls lock out and the game resets.
Years ago, I remember playing Donkey Kong Country hooked up inside an arcade cabinet. They had a timer and the game would reset and controller would stop working when the time expires. Wish I had asked the owner how it was wired.
That sounds similar to DKC competition, in some sort of arcade cab https://snescentral.com/article.php?id=0910
Pretty sure it wasn't the competition cart. The owner of the arcade saw potential in people wanting to play Snes, and not being able to own one this was the only way to experience it.
