Returns the recording of a completed call in one of three shapes, chosen by the request itself: send Accept: application/json for a temporary URL, add download=1 for the audio bytes as an attachment, or make a plain GET (as an <audio> element does) and be redirected. The URL is valid for one hour and is served directly from storage, so it works without your API key once issued — treat it as a secret. The same access rule as the call record applies: one-to-one calls between two of your extensions stay visible only to the people on them.