--- a/src/source/appextend.rst	Tue Jun 05 11:50:24 2018 +0200
+++ b/src/source/appextend.rst	Tue Jun 05 12:05:59 2018 +0200
@@ -11,3 +11,4 @@
     howto-portlet
     howto-renderer
     howto-paragraph
+    howto-skin