diff --git a/user.js b/user.js
index c9ad677..b773e96 100644
--- a/user.js
+++ b/user.js
@@ -1296,10 +1296,10 @@ user_pref("devtools.chrome.enabled", false);
 user_pref("devtools.debugger.remote-enabled", false);
 user_pref("devtools.webide.enabled", false);
 user_pref("devtools.webide.autoinstallADBExtension", false); // [FF64+]
-/* 2609: disable MathML (Mathematical Markup Language) [FF51+]
+/* 2609: disable MathML (Mathematical Markup Language) [FF51+] [SETUP-HARDEN]
  * [TEST] http://browserspy.dk/mathml.php
  * [1] https://bugzilla.mozilla.org/1173199 ***/
-user_pref("mathml.disabled", true);
+   // user_pref("mathml.disabled", true);
 /* 2610: disable in-content SVG (Scalable Vector Graphics) [FF53+]
  * [SETUP-WEB] Expect breakage incl. youtube player controls. Best left for a "hardened" profile.
  * [1] https://bugzilla.mozilla.org/1216893 ***/