Why such a strange property output in the Chrome debugger?

Question

JavaScript

I've been learning JS for a while now. There is a form with various elements. Accessing it with code
document.forms[0]
Actually, I can access its elements with code The
document.forms[0].elements[n]
question is why when viewing the forms[0] property in the Chrome debuggers , the values ​​of the elements property are displayed? This is confusing me, please explain what is the matter here.