Applications relying on ICE often need to know whether a connection is relayed via a TURN server and which TURN server and TURN server protocol an ICE candidate was gathered from. https://w3c.github.io/webrtc-pc/#rtcicecandidate-interface gets implementations for two new properties for RTCIceCandidate objects emitted from the 'icecandidate' event. https://github.com/w3c/webrtc-pc/pull/2773 added the url of the STUN or TURN server a local ICE candidate of type 'srflx' or 'relay' was gathered from. https://github.com/w3c/webrtc-pc/pull/2763 added the relay protocol (i.e. whether the candidate was gathered via TURN/UDP, TURN/TCP or TURN/TLS) a local ice candidates of type 'relay' was gathered from. These properties are already available in the getStats API as RTCIceCandidateStats.
This addition allows web developers to gain more insight into the origins of a local ice candidate. This is e.g. used in the STUN/TURN server test page: https://webrtc.github.io/samples/src/content/peerconnection/trickle-ice/