What will the result be and what FP pattern does Tree<T> represent?

type Tree<T> =
  | { type: "leaf"; value: T }
  | { type: "node"; left: Tree<T>; right: Tree<T> };

const sumTree = (tree: Tree<number>): number =>
  tree.type === "leaf"
    ? tree.value
    : sumTree(tree.left) + sumTree(tree.right);

const myTree: Tree<number> = {
  type: "node",
  left: { type: "leaf", value: 1 },
  right: {
    type: "node",
    left: { type: "leaf", value: 2 },
    right: { type: "leaf", value: 3 },
  },
};

console.log(sumTree(myTree));