The unregister() method was used to ask the system to unregister and delete the specified endpoint. In the updated API, a subscription is can be unregistered via the PushSubscription.unsubscribe() method.
The W3C Push API offers some exciting new functionality for developers to use in web applications: this article provides an introduction to getting Push notifications setup and running, with a simple demo.
The endpoint read-only property of the PushSubscription interface returns a DOMString containing the subscription ID associated with the push subscription.