--- a/b2g/confvars.sh
+++ b/b2g/confvars.sh
@@ -1,18 +1,16 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 MOZ_APP_BASENAME=B2G
 MOZ_APP_VENDOR=Mozilla
 
 MOZ_APP_VERSION=17.0a1
-
-MOZ_UA_OS_AGNOSTIC=1
 MOZ_APP_UA_NAME=Firefox
 
 MOZ_BRANDING_DIRECTORY=b2g/branding/unofficial
 MOZ_OFFICIAL_BRANDING_DIRECTORY=b2g/branding/official
 # MOZ_APP_DISPLAYNAME is set by branding/configure.sh
 
 MOZ_SAFE_BROWSING=
 MOZ_SERVICES_SYNC=1