diff -r f4f5bf8b4d17 -r 72246b13bd72 hgext3rd/topic/__init__.py
--- a/hgext3rd/topic/__init__.py	Wed Mar 30 22:02:52 2016 -0700
+++ b/hgext3rd/topic/__init__.py	Wed Mar 30 22:03:44 2016 -0700
@@ -335,6 +335,8 @@
     rebase = extensions.find("rebase")
     extensions.wrapfunction(rebase, '_makeextrafn', newmakeextrafn)
 
+## preserve topic during import/export
+
 def _exporttopic(seq, ctx):
     topic = ctx.topic()
     if topic: