diff --git a/.hgtags b/.hgtags
index 97bccc1f0..29ee5b2a0 100644
--- a/.hgtags
+++ b/.hgtags
@@ -384,3 +384,4 @@ e2f49dfe838b40dcc6a144db6c7e8f763c699ca8 FIREFOX_4_0_1_RELEASE_RUNTIME
 d6d1a1a8b6387d0de97eaf32dd037f1f2193b0aa FIREFOX_5_0b5_BUILD1
 d6d1a1a8b6387d0de97eaf32dd037f1f2193b0aa FIREFOX_5_0b5_RELEASE
 e734787c29363af172f00318846feec97e29a440 FIREFOX_5_0b5_RELEASE_RUNTIME
+e734787c29363af172f00318846feec97e29a440 FIREFOX_5_0b5_BUILD1_RUNTIME