diff -crB old/content/startpage.html new/content/startpage.html
*** old/content/startpage.html	2009-10-12 14:52:41.000000000 +0400
--- new/content/startpage.html	2010-02-23 19:21:33.730472358 +0300
***************
*** 10,30 ****
  
  var prefs = Components.classes["@mozilla.org/preferences-service;1"]
             .getService(Components.interfaces.nsIPrefBranch);
! var userAgentLocale = null;
! try {
!   var userAgentLocaleLocalized = null;
! 
!   try {
!     userAgentLocaleLocalized = prefs.getComplexValue("general.useragent.locale",
!                                                      Components.interfaces.nsIPrefLocalizedString);
!   } catch (e) {}
! 
!   if (userAgentLocaleLocalized) {
!       userAgentLocale = userAgentLocaleLocalized.toString();
!   } else {
!       userAgentLocale = prefs.getCharPref("general.useragent.locale");
!   }
! } catch (e) { userAgentLocale = "en-US";}
  
  function get_valid_offlinehomepage() {
     var canonicalLangCode = userAgentLocale.replace("-","_");
--- 10,16 ----
  
  var prefs = Components.classes["@mozilla.org/preferences-service;1"]
             .getService(Components.interfaces.nsIPrefBranch);
! var userAgentLocale = navigator.appVersion.slice(10,-1);
  
  function get_valid_offlinehomepage() {
     var canonicalLangCode = userAgentLocale.replace("-","_");
Только в new/content: startpage.html~