https://support.mozilla.org/fr/kb/tracking-protection-pbm
« To see which resources are being blocked, you can open the web console and look for messages under the Security tab. »
http://www.ghacks.net/2015/09/20/firefox-43-tracking-protection-with-blocklist-selection/
« Firefox 43 will ship with two lists by default that users can select between. The initial list that ships with Firefox 42 is enabled by default, and options to switch to another list are provided in the preferences. »