__proto__ VS. prototype in JavaScript

Question

This figure again shows that every object has a prototype. Constructor function Foo also has its own __proto__ which is Function.prototype, a

Answer 1

my understanding is: __proto__ and prototype are all served for the prototype chain technique . the difference is functions named with underscore(like __proto__) are not aim for developers invoked explicitly at all. in other words, they are just for some mechanisms like inherit etc. they are 'back-end'. but functions named without underscore are designed for invoked explicitly, they are 'front-end'.