--- a/mercurial/keepalive.py	Wed Oct 03 09:43:01 2018 -0700
+++ b/mercurial/keepalive.py	Mon Oct 01 12:06:36 2018 -0700
@@ -615,6 +615,10 @@
     return safegetresponse
 
 class HTTPConnection(httplib.HTTPConnection):
+    # url.httpsconnection inherits from this. So when adding/removing
+    # attributes, be sure to audit httpsconnection() for unintended
+    # consequences.
+
     # use the modified response class
     response_class = HTTPResponse
     send = safesend