persona x grata
When it comes to inheritance, JavaScript only has one construct: objects. Each object has a private property which holds a link to another object called its prototype. That prototype object has a prototype of its own, and so on until an object is reached with null as its prototype. By definition, null has no prototype, and acts as the final link in this prototype chain.
[[Prototype]] скорее всего имеется ввиду, оно скрыто и ссылается на прототип, но не надо путать с prototype у функций