Mystery Cartridge for Genesis...what is it really?

So here is an interesting question. I bought this supposedly pirate cart for the genesis thinking it was a multi cart but no games showed up. I decided to insert a cart on top of it since it has a connection thing for carts and the game started but with weird sounding music. So my question is, what the hell does this cart do? A friend of mine told me it's a region type of cart that'll let you play carts that are only for specific regions. Maybe it is or maybe not. Anyways, shoot me up with some info on this cart. I'm uploading four photos I took of the cart. Cya