diff --git a/.hgtags b/.hgtags
index 051535f46943..6321d26c59a3 100644
--- a/.hgtags
+++ b/.hgtags
@@ -138,3 +138,4 @@ f9605772a0c9098ed1bcaa98089b2c944ed69e9b FIREFOX_BETA_55_BASE
 f7e9777221a34f9f23c2e4933307eb38b621b679 FIREFOX_NIGHTLY_57_END
 40a14ca1cf04499f398e4cb8ba359b39eae4e216 FIREFOX_BETA_58_BASE
 1f91961bb79ad06fd4caef9e5dfd546afd5bf42c FIREFOX_NIGHTLY_58_END
+5faab9e619901b1513fd4ca137747231be550def FIREFOX_NIGHTLY_59_END