More detail: Yes, WebRTC contains several methods for routing through NATs -- ICE, STUN by default (using your browser's default STUN server), optionally TURN.

My browser manufacturer has a STUN server? Where can I find that? (e.g., for Chrome or Firefox)

Edit: AFAICT, this isn't correct. Your browser has no notion of a "default" (or any other) STUN/TURN server. The JavaScript doing WebRTC has to specify one.

That said Google runs one, at stun.l.google.com:19302; but it isn't clear if that's something third-parties could or should make use of (or if Google even permits such activity), though it seems like plenty of examples (and perhaps even real-world uses) make use of it.

In the past, I've seen this Google STUN server used on Chrome when none is supplied by the user JS. This may have changed in recent years.