I hope webrtc isn't authorized by default by browsers.I want to give explicit consent.It should even have been that way for ajax requests.
However, like you pointed out, there are other ways than XHR to leak data if JS is enabled.
If JS is not enabled, the kinds of data that can be leaked is fewer (perhaps screen resolution and size).
Would welcome expert comments on our issue tracker: https://github.com/UprootLabs/gngr/issues/90