Brain fruit!

While hiking in Gishwati, I encountered a most delicious and novel fruit. My Rwandan guides in the forest called it umwufe. My coworkers, as we watched the World Cup final and munched on its kernels, said that it's icyufu. I don't know if it has an English name, so I'm dubbing it brain fruit, because that's what it looks like - anyone know what it really is? It's a yellow-brown assemblage of partially edible kernels around what I think is an inedible (or at least unappetizing) core.

To eat it, snap off kernels and suck on them. The taste is a bit like the little sour-but-sweet Chinese cherries. Each kernel has a pit in it, some small enough to eat and others as big and hard as a marble. I ate the slightly stringy fruit inside the kernels and threw out the leathery skin.

Green ones on a tree, and ripe ones on the ground waiting for chimps to eat them.