If you aren’t sure what to look for in your Nintendo games to find these. They only came out in the original prints of the games when Nintendo didn’t have enough time to produce enough 9 pin adapters. So the easier way for them at the time was to use converters with famicom boards.
So, if you are out looking for them to complete your variants or to make some quick cash or trade money, you will need to look for flat tab top games with 5 screws in the back of the cart.
The only known games with them in them are these.
Clu Clu Land
Donkey Kong Jr.
Mike Tyson’s Punch-Out!!
Raid on Bungeling Bay
Wizards and Warriors
Happy hunting and share with your pals.
X’s and O’s