diff --git a/language/types/string.xml b/language/types/string.xml
index 25c8733c9f..617cdb6fc2 100644
--- a/language/types/string.xml
+++ b/language/types/string.xml
@@ -167,7 +167,8 @@ echo 'Variables do not $expand $either';
        <entry><literal>\[0-7]{1,3}</literal></entry>
        <entry>
         the sequence of characters matching the regular expression is a
-        character in octal notation
+        character in octal notation, which silently overflows to fit in a byte
+        (e.g. "\400" === "\000")
        </entry>
       </row>
       <row>
@@ -202,7 +203,7 @@ echo 'Variables do not $expand $either';
     details.
    </para>
   </sect3>
-  
+
   <sect3 xml:id="language.types.string.syntax.heredoc">
    <title>Heredoc</title>
 
@@ -210,7 +211,7 @@ echo 'Variables do not $expand $either';
     A third way to delimit <type>string</type>s is the heredoc syntax:
     <literal>&lt;&lt;&lt;</literal>. After this operator, an identifier is
     provided, then a newline. The <type>string</type> itself follows, and then
-    the same identifier again to close the quotation. 
+    the same identifier again to close the quotation.
    </simpara>
 
    <simpara>