Tor Browser Fingerprint
Tor Browser and Tails version fingerprinting in Javascript (and some CSS). The PoC can also detect if Tor Browser is running on a Mac OS X. Works up to medium-high privacy settings.
Online demo at: https://tor.triop.se
Screenshots
Demo Video
Responsible Disclosure
The Tor-project was contacted in Jan 2016. But no changes has been made since the root of the problem is located in Firefox.