diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 68df7d70..620fa7f1 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -82,7 +82,7 @@ operator precedence like `2*a + 3*b` instead of `a * a + 3 * b`. Generally, don'
 dropped. Don't use the `+` operator for appending multiple strings. Use formatting instead.
 
 **E228** missing whitespace around modulo operator  
-**Reason:** Column alignment.
+**Reason:** See reason for E226. Formatting `%` like `/` and `*` should be possible.
 
 **E241:** multiple spaces after ‘,’  
 **Reason:** Column alignment.