Describes the contents and behavior or a WebHook. A WebHook is similar to a subscription in a pub/sub system in that it allows the subscriber to indicate when and how event notifications should get dispatched and where they should get dispatched to. A WebHook is registered and managed on a per user basis which means that each user has a separate set of WebHooks that can get trigged by actions executed by that user. That is, user A will not see a WebHook fired for an action performed by user B.