diff --git a/mozilla/modules/libpref/public/nsIPrefBranch.idl b/mozilla/modules/libpref/public/nsIPrefBranch.idl
new file mode 100644
index 00000000000..ef17c67d21d
--- /dev/null
+++ b/mozilla/modules/libpref/public/nsIPrefBranch.idl
@@ -0,0 +1,134 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ *
+ * The contents of this file are subject to the Netscape Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ *
+ * The Original Code is Mozilla Communicator client code.
+ *
+ * The Initial Developer of the Original Code is Netscape Communications
+ * Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998 Netscape Communications Corporation. All
+ * Rights Reserved.
+ *
+ * Contributor(s):
+ * Alec Flett <alecf@netscape.com>
+ */
+
+#include "nsISupports.idl"
+#include "nsIFileSpec.idl"
+#include "nsIPrefListener.idl"
+
+native PrefEnumerationFunc(PrefEnumerationFunc);
+
+[scriptable, uuid(56c35506-f14b-11d3-99d3-ddbfac2ccf65)]
+interface nsIPrefBranch : nsISupports
+{
+    /**
+     * the root of this branch, such as "browser."
+     */
+    readonly attribute string root;
+    
+    /*
+     * standard methods for accessing prefs
+     */
+    boolean getBoolPref(in string prefName);
+    void    setBoolPref(in string prefName, in long value);
+    
+    long    getIntPref(in string prefName);
+    void    setIntPref(in string prefName, in long value);
+    
+    string  getCharPref(in string prefName);
+    void    setCharPref(in string prefName, in string value);
+
+    wstring getUnicharPref(in string prefName);
+    void    setUnicharPref(in string prefName, in wstring value);
+
+    /* going away in favor of nsIFile! */
+    nsIFileSpec getFileSpecPref(in string prefName);
+    void setFileSpecPref(in string prefName, in nsIFileSpec value);
+
+    void clearPref(in string prefName);
+    
+    /* do we need other prefs like color, rect, etc?
+       or maybe we should just have a prefTranslation service
+       that translates a string pref into any other type */
+    
+    /*
+     * same as above but for getting default prefs
+     */
+    boolean getDefaultBoolPref(in string prefName);
+    void    setDefaultBoolPref(in string prefName in boolean value);
+    
+    long    getDefaultIntPref(in string prefName);
+    void    setDefaultIntPref(in string prefName, in long value)
+    
+    string  getDefaultCharPref(in string prefName);
+    void    setDefaultCharPref(in string prefName, in string value);
+
+    wstring getDefaultUnicharPref(in string prefName);
+    void    setDefaultUnicharPref(in string prefName, in wstring value);
+
+    /* going away in favor of nsIFile! */
+    nsIFileSpec getDefaultFileSpecPref(in string prefName);
+    void setDefaultFileSpecPref(in string prefName, in nsIFileSpec value);
+
+    /*
+     * branch-level operations
+     */
+
+    /**
+     * clearBranch
+     * 
+     * clears all prefs starting at the given pref prefix
+     * pass in null or "" to clear this branch
+     */
+    void clearBranch(in string startingAt);
+    
+    /**
+     * EnumerateChildren
+     *
+     * Call back function "callback" with every preference string
+     * having prefix "parent". Pass "data" to "callback" when calling.
+     * 
+     * @param parent A string representation of a prefix of preferences
+     * @param callback A function to call back for each matching preference
+     * @param data A piece of data to pass on to the callback
+     */
+    [noscript]
+    void EnumerateChildren(in string parent,
+                           in PrefEnumerationFunc callback,
+                           in voidStar data);
+    /*
+     * Listeners/Callbacks
+     */
+
+    /**
+     * addListener
+     * removeListener - for adding/removing interfaces that listen on
+     *                  preference changes
+     */
+    void addListener(in string prefName, in nsIPrefListener listener);
+    void removeListener(in string prefName, in nsIPrefListener listener);
+
+
+    /**
+     * registerCallback
+     * unregisterCallback - old C-style registration system
+     */
+    [noscript] void registerCallback(in string domain,
+                                     in PrefChangedFunc callback,
+                                     in voidStar closure);
+    [noscript] void unregisterCallback(in string domain,
+                                       in PrefChangedFunc callback,
+                                       in voidStar closure);
+    
+                           
+};
+
diff --git a/mozilla/modules/libpref/public/nsIPrefListener.idl b/mozilla/modules/libpref/public/nsIPrefListener.idl
index 988040c9b79..32f8b211285 100644
--- a/mozilla/modules/libpref/public/nsIPrefListener.idl
+++ b/mozilla/modules/libpref/public/nsIPrefListener.idl
@@ -1,4 +1,4 @@
-/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  *
  * The contents of this file are subject to the Netscape Public
  * License Version 1.1 (the "License"); you may not use this file
@@ -21,14 +21,26 @@
  * Alec Flett <alecf@netscape.com>
  */
 
+#include "nsISupports.idl"
+
 [scriptable, uuid(b08d2804-1dd1-11b2-80ea-9fee2622f017)]
 interface nsIPrefListener : nsISupports
 {
-  /**
-   * called when the given pref changes
-   *
-   * @param prefName
-   */
-  void prefChanged(in string prefName);
+    /**
+     * called when the given pref changes
+     *
+     * @param prefName - name of pref
+     */
+    void onBoolPrefChanged(in string prefName,
+                           in boolean oldValue, in boolean newValue);
+  
+    void onIntPrefChanged(in string prefName,
+                          in long oldValue, in long newValue);
+  
+    void onCharPrefChanged(in string prefName,
+                           in string oldValue, in string newValue);
+  
+    void onUnicharPrefChanged(in string prefName,
+                              in wstring oldValue, in string newValue);
+};
 
-}