WindowClient: ancestorOrigins property

The ancestorOrigins read-only property of the WindowClient interface is an array of strings listing the origins of all ancestors of the browsing context represented by this WindowClient in reverse order.

The first element in the array is the origin of this window's parent, and the last element is the origin of the top-level browsing context. If this window is itself a top-level browsing context, then ancestorOrigins is an empty array.