--- a/hgext/progress.py	Fri Apr 10 23:12:33 2015 -0700
+++ b/hgext/progress.py	Tue Apr 28 16:44:37 2015 -0400
@@ -40,6 +40,10 @@
 import threading
 
 from mercurial.i18n import _
+# Note for extension authors: ONLY specify testedwith = 'internal' for
+# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
+# be specifying the version(s) of Mercurial they are tested with, or
+# leave the attribute unspecified.
 testedwith = 'internal'
 
 from mercurial import encoding