It's part of the markings you'll see on some tabbies ....as I recall they are delightfully called "vest buttons" <G>. It's related to coat pattern, not breed.
There are different kinds of tabbies, some have spots or strips. But I'm not sure if your kitty is an Ocicat because they only come in brown I think. And Bengal have more spots on their bodies. It doesn't matter if your kitty is Ocicat or Bengal, it is stiil cute and adorable no matter what.
My baby gurl, Zebra has spots on her tummy too. I have no idea what she is. I think she looks like a Maine Coon, but what do I know.. What do you guys think?