Issue #26736: Used HTTPS for external links in the documentation if possible.
diff --git a/Doc/library/difflib.rst b/Doc/library/difflib.rst
index 03e8cb8..ead6b7a 100644
--- a/Doc/library/difflib.rst
+++ b/Doc/library/difflib.rst
@@ -594,7 +594,7 @@
      work.
 
    * `Simple version control recipe
-     <http://code.activestate.com/recipes/576729/>`_ for a small application
+     <https://code.activestate.com/recipes/576729/>`_ for a small application
      built with :class:`SequenceMatcher`.