Index: head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
===================================================================
--- head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
+++ head/en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml
@@ -5174,6 +5174,21 @@
 	not present, it is considered to be a
 	<literal>no-<replaceable>permission</replaceable></literal>.</para>
 
+      <warning>
+	<para>Some missing permissions will prevent a port (and all
+	  ports depending on it) from being usable by package
+	  users:</para>
+
+	<para>A port without the <literal>auto-accept</literal>
+	  permission will never be be built and all the ports
+	  depending on it will be ignored.</para>
+
+	<para>A port without the <literal>pkg-mirror</literal>
+	  permission will be removed, as well as all the ports
+	  depending on it, after the build and they will ever end up
+	  being distributed.</para>
+      </warning>
+
       <example xml:id="licenses-license_perms-ex1">
 	<title>Nonstandard License</title>