--- a/hgext/rebase.py	Wed Nov 25 18:26:48 2015 +0100
+++ b/hgext/rebase.py	Sat Nov 28 04:11:14 2015 -0500
@@ -615,7 +615,10 @@
         if commitmsg is None:
             commitmsg = ctx.description()
         keepbranch = keepbranches and repo[p1].branch() != ctx.branch()
-        extra = {'rebase_source': ctx.hex()}
+        extra = ctx.extra().copy()
+        if not keepbranches:
+            del extra['branch']
+        extra['rebase_source'] = ctx.hex()
         if extrafn:
             extrafn(ctx, extra)