In the early days of Javascript, there was one master global symbol and everything that was available in the global scope whether it was part of the language itself or part of the browser environment was a property of that master global.

In the browser, that master global is the window object. Thus, you see many things on the window object that are available globally like the Array constructor.

I would guess that this is a side effect of that fact that Javascript was first designed to run in a browser and was not initially a completely stand-alone language with a stand-alone specification.

More recent revisions to the language specification are not adding some new things to the window object any more. For example, when you declare an ES6 class such as:

class Foo {
    constructor(greeting) {
        this.greeting = greeting;
    }
}

You will not find Foo on the window object even though it may be globally available in the browser.

As others have said, the color difference in the debug output has to do with whether the symbols are enumerable or not which is a technical distinction on whether the property shows up in something like Object.keys() or a for/in loop. The property is still there and is accessible either way.