diff --git a/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in b/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in
index 05b790feb8e..b68bf1f3654 100644
--- a/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in
+++ b/mozilla/toolkit/mozapps/extensions/src/nsExtensionManager.js.in
@@ -75,7 +75,6 @@ const FILE_CHROME_MANIFEST            = "contents.rdf";
 const FILE_WASINSAFEMODE              = "Safe Mode";
 const FILE_INSTALLED_EXTENSIONS       = "installed-extensions.txt"
 const FILE_INSTALLED_EXTENSIONS_PROCESSED = "installed-extensions-processed.txt"
-#expand const TARGET_OS                                 = "__OSARCH__";
 
 const KEY_PROFILEDIR                  = "ProfD";
 const KEY_APPDIR                      = "XCurProcD";
@@ -3113,7 +3112,6 @@ nsRDFItemUpdater.prototype = {
     dsURI = dsURI.replace(/%APP_ID%/g, this._updater._appID);
     dsURI = dsURI.replace(/%APP_VERSION%/g, this._updater._appVersion);
     dsURI = dsURI.replace(/%REQ_VERSION%/g, 1);
-    dsURI = dsURI.replace(/%APP_OS%/g, TARGET_OS);
     
     // escape() does not properly encode + symbols in any embedded FVF strings.
     dsURI = dsURI.replace(/\+/g, "%2B");