4503: RFP mozAddonManager

Inactive: 1: currently only three sites (hard-coded) can access this, all run by Mozilla 2: it is likely to be used on the new AMO site to determine your Firefox version

user.js

@@ -1594,6 +1594,9 @@ user_pref("privacy.resistFingerprinting", true); // (hidden pref) (not hidden FF
  * [2] https://hardware.metrics.mozilla.com/ ***/
 user_pref("privacy.window.maxInnerWidth", 1600); // (hidden pref)
 user_pref("privacy.window.maxInnerHeight", 900); // (hidden pref)
+/* 4503: disable mozAddonManager Web API (FF57+)
+ * [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1384330 ***/
+   // user_pref("privacy.resistFingerprinting.block_mozAddonManager", true); // (hidden pref)
 
 /*** 4600: RFP (4500) ALTERNATIVES [SETUP]
    * IF you DO use RFP (see 4500) then you DO NOT need these redundant prefs. In fact,