--- a/hgext3rd/evolve/__init__.py	Tue May 23 10:49:59 2017 +0200
+++ b/hgext3rd/evolve/__init__.py	Wed May 24 16:43:04 2017 +0200
@@ -70,6 +70,13 @@
   # (recommended 'off' for developer repositories)
   # (recommended 'yes' for server (default))
   obshashrange.warm-cache = no
+
+It is recommended to enable the blackbox extension to gather useful
+data about the experiment. It is shipped with Mercurial so no extra
+install needed.
+
+    [extensions]
+    blackbox =
 """
 
 evolutionhelptext = """