localize.

browser/components/prefwindow/content/pref-themes.xul

@@ -47,8 +47,8 @@
 
   <tabbox flex="1">
   <tabs>
-    <tab label="Themes"/>
-    <tab label="Extensions"/>
+    <tab label="&themesTab.label;"/>
+    <tab label="&extensionsTab.label;"/>
   </tabs>
   <tabpanels flex="1">
   <vbox flex="1">

browser/components/prefwindow/locale/pref-themes.dtd

@@ -16,3 +16,5 @@
 <!ENTITY  author.label            "Author">
 
 <!ENTITY  getNewThemes.label      "Get New Themes">
+<!ENTITY  themesTab.label         "Themes">
+<!ENTITY  extensionsTab.label     "Extensions">