Presentation.receiver

In a receiving user agent, the receiver attribute MUST return the PresentationReceiver instance associated with the receiving browsing context and created by the receiving user agent when the receiving browsing context is created. In any other browsing context, it MUST return null.

A user agent that is a receiving user agent but not a controlling user agent MUST always return null for the defaultRequest attribute. It MUST treat setting the defaultRequest attribute as a no-op.

A user agent that is a controlling user agent but not a receiving user agent MUST always return null for the receiver attribute.