Privacy Badger currently detects tracking via regular cookies, HTML5 local storage 'cookies', and canvas fingerprinting, with more methods aimed to be supported in future releases
[0] https://github.com/samyk/evercookie/
[1] http://www.theregister.co.uk/2015/01/30/verizon_uidh_super_c...
Good starting places for the current heuristics:
https://github.com/EFForg/privacybadgerchrome/blob/stable/sr...
https://github.com/EFForg/privacybadgerchrome/blob/master/sr... https://github.com/EFForg/privacybadgerchrome/blob/stable/sr...