diff --git a/documentation/ref-manual/ref-classes.xml b/documentation/ref-manual/ref-classes.xml
index 868a0da5d4..3e7662e146 100644
--- a/documentation/ref-manual/ref-classes.xml
+++ b/documentation/ref-manual/ref-classes.xml
@@ -186,6 +186,8 @@
         binary from source.
         The binary package is extracted and new packages in the configured
         output package format are created.
+        Extraction and installation of proprietary binaries is a good example
+        use for this class.
         <note>
             For RPMs and other packages that do not contain a subdirectory,
             you should specify a "subdir" parameter.