#Fedify has a side effect that when you call the getter method of an Activity Vocabulary object, the property that was internally a URI is populated with the actual ActivityStreams object. Today, someone at Ghost gave us a cool term for this: #hydration.
fedify.dev
Vocabulary | Fedify
The Activity Vocabulary is a collection of type-safe objects that represent the Activity Vocabulary and the vendor-specific extensions. This section explains the key features of the objects.