User Agent: Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Firefox/49.0 Build ID: 20100101 Steps to reproduce: I went to privacy.donottrackheader.enabled and set it to false to disable the DNT header. Actual results: When I go to https://www.browserleaks.com/donottrack it shows that the DNT header is still active. Expected results: It should be able to disable the DNT header. I was able to finally locate the conflicting variables to disable the DNT header, these two settings must also be set to false. But I do not think all tracking protection should have to be disabled just to turn off the header? pref("privacy.trackingprotection.enabled", false); pref("privacy.trackingprotection.pbmode.enabled", false);
The content of the in-content preferences dialog to manage the DNT pref explains that tracking protection will cause the header to be sent whenever it's active. This was done in bug 1274712 in response to bug 1258033. So this is expected, and there's UI in the prefpane, so I'm going to mark this as wontfix.