diff --git a/en_US.ISO8859-1/books/porters-handbook/book.sgml b/en_US.ISO8859-1/books/porters-handbook/book.sgml
index 7d0d93020c..0a49c430e5 100644
--- a/en_US.ISO8859-1/books/porters-handbook/book.sgml
+++ b/en_US.ISO8859-1/books/porters-handbook/book.sgml
@@ -3027,6 +3027,12 @@ DISTFILES+=             <replaceable>foo.tar.gz</replaceable>
 ALWAYS_KEEP_DISTFILES=  yes
 .endif</programlisting>
 	</example>
+
+	<para>When adding extra files to <makevar>DISTFILES</makevar>,
+	  make sure you also add them to <filename>distinfo</filename>.
+	  Also, the additional files will normally be extracted into
+	  <makevar>WRKDIR</makevar> as well, which for some ports may
+	  lead to undesirable sideeffects and require special handling.</para>
       </sect2>
     </sect1>