Breadfruit is a kind of tropical fruit that grows on a tree. Typically, Americans think of fruit as sweet things like bananas, apples, or oranges. Breadfruit is nothing like this. Instead, breadfruit is very starchy. In terms of what it tastes like and how you would use it, it is much more like a potato than like an apple.
Breadfruit is native to areas around the Western Pacific Ocean. From there, it spread throughout the Pacific as Polynesian and other people populated the various islands of the region. When Europeans came to the Pacific, they discovered breadfruit and brought it to other tropical regions such as Central America and Africa.
Breadfruit was one of the staple foods of the ancient Polynesians (Mafatu’s people were Polynesian). It was eaten in a variety of different ways. It could be boiled, baked in underground ovens, or pounded up and left to ferment. Today, breadfruit is also cooked in other ways that have been made possible by modern technology. For example, I have eaten breadfruit chips that are deep fried sort of like potato chips.
So, when Mafatu eats breadfruit, he is eating a fruit that grows in a large tree but that is much more like a potato than like any fruits that we have in the Mainland United States.