Index: mozilla-esr31/browser/app/profile/firefox.js
===================================================================
--- mozilla-esr31/browser/app/profile/firefox.js
+++ mozilla-esr31/browser/app/profile/firefox.js	2014-09-06 00:39:07.548100720 +0200
@@ -269,7 +269,7 @@
 #endif
 
 // At startup, check if we're the default browser and prompt user if not.
-pref("browser.shell.checkDefaultBrowser", true);
+pref("browser.shell.checkDefaultBrowser", false);
 pref("browser.shell.shortcutFavicons",true);
 
 // 0 = blank, 1 = home (browser.startup.homepage), 2 = last visited page, 3 = resume previous browser session