1603 -> inactive

Yes it's pretty much useless. Yes it's fingerprintable, and what that entropy is, who knows. Since it's sent regardless with ETP, which we enable in all windows, then who cares. And if you don't use ETP in all windows, then I don't care either - just saying

user.js

@@ -730,9 +730,9 @@ user_pref("network.http.referer.XOriginPolicy", 2);
  * 0=send full URI (default), 1=scheme+host+port+path, 2=scheme+host+port ***/
 user_pref("network.http.referer.XOriginTrimmingPolicy", 2);
 /* 1603: enable the DNT (Do Not Track) HTTP header
- * [NOTE] DNT is enforced with Enhanced Tracking Protection regardless of this pref
+ * [NOTE] DNT is enforced with Enhanced Tracking Protection (2710)
  * [SETTING] Privacy & Security>Enhanced Tracking Protection>Send websites a "Do Not Track" signal... ***/
-user_pref("privacy.donottrackheader.enabled", true);
+   // user_pref("privacy.donottrackheader.enabled", true);
 
 /*** [SECTION 1700]: CONTAINERS
    If you want to really leverage containers, we recommend Temporary Containers [2].