--- a/hgext/highlight/__init__.py	Fri Apr 10 23:12:33 2015 -0700
+++ b/hgext/highlight/__init__.py	Tue Apr 28 16:44:37 2015 -0400
@@ -24,6 +24,10 @@
 import highlight
 from mercurial.hgweb import webcommands, webutil, common
 from mercurial import extensions, encoding
+# 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'
 
 def filerevision_highlight(orig, web, tmpl, fctx):