1 files changed, 10 insertions, 1 deletions

diff --git a/documentation/poky-ref-manual/ref-structure.xml b/documentation/poky-ref-manual/ref-structure.xml
index c2644df374..166907ceef 100644
--- a/documentation/poky-ref-manual/ref-structure.xml
+++ b/documentation/poky-ref-manual/ref-structure.xml
@@ -247,11 +247,20 @@
         <title><filename>build/conf/bblayers.conf</filename></title>
 
         <para>
-            This file defines layers, which is a directory tree, traversed (or walked) by BitBake. 
+            This file defines layers, which are directory trees, traversed (or walked) by BitBake.
             If <filename>bblayers.conf</filename> 
             is not present, it is created from <filename>bblayers.conf.sample</filename> when 
             you <filename>source</filename> the environment setup script.
         </para>
+
+        <para>
+            The <filename>bblayers.conf</filename> file uses the
+            <link linkend='var-BBLAYERS'><filename>BBLAYERS</filename></link> variable to
+            list the layers BitBake tries to find.
+            The file uses the
+            <link linkend='var-BBLAYERS_NON_REMOVABLE'><filename>BBLAYERS_NON_REMOVABLE</filename></link>
+            variable to list layers that must not be removed.
+        </para>
     </section>
 
     <section id='structure-build-conf-sanity_info'>