diff --git a/defaults/main.yml b/defaults/main.yml
index ae29c16..091d9e3 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -79,6 +79,7 @@ spamassassin_shortcircuit_bayes_rules:
   - { key: 'BAYES_99', value: 'spam' }
   - { key: 'BAYES_00', value: 'ham' }
 
+# See https://cwiki.apache.org/confluence/display/SPAMASSASSIN/WritingRules
 spamassassin_local_rules: []
 #  - "score DKIM_VALID 0.001"
 #  - "score DKIM_INVALID 2"