diff --git a/.hgtags b/.hgtags
index 53559af0e1ef..993fc16d821f 100644
--- a/.hgtags
+++ b/.hgtags
@@ -324,3 +324,4 @@ e571552c235724fbce9b1ceaedf4bff73093eaa7 FIREFOX_BETA_136_BASE
 f27925f3d6f792efb037cdb55bb98b972c11c1c6 FIREFOX_BETA_138_BASE
 dce1a8cec5da4af61753f9db5fbe60a85299f1d9 FIREFOX_NIGHTLY_138_END
 2149fbb1f153564d301921fd6d536ba93cbdbb65 FIREFOX_BETA_139_BASE
+6ca7d74193b51df2c011b66b4bc1fe3eb233c90d FIREFOX_NIGHTLY_139_END