If doc’s browsing context's opener browsing context is not its top-level browsing context, reject p.
I don't understand how this would work as most child browsing contexts wouldn't have an opener browsing context. Does this mean "is not a top-level browsing context" or something else?
I don't understand how this would work as most child browsing contexts wouldn't have an opener browsing context. Does this mean "is not a top-level browsing context" or something else?