diff --git a/documentation/ref-manual/ref-structure.xml b/documentation/ref-manual/ref-structure.xml
index 56927cd9f5..e0209c1afa 100644
--- a/documentation/ref-manual/ref-structure.xml
+++ b/documentation/ref-manual/ref-structure.xml
@@ -824,6 +824,21 @@
         </para>
     </section>
 
+    <section id='structure-meta-conf-machine-sdk'>
+        <title><filename>meta/conf/machine-sdk/</filename></title>
+
+        <para>
+            The OpenEmbedded build system searches this directory for
+            configuration files that correspond to the value of
+            <link linkend='var-SDKMACHINE'><filename>SDKMACHINE</filename></link>.
+            By default, 32-bit and 64-bit x86 files ship with the Yocto
+            Project that support some SDK hosts.
+            However, it is possible to extend that support to other SDK hosts
+            by adding additional configuration files in this subdirectory
+            within another layer.
+        </para>
+    </section>
+
     <section id='structure-meta-files'>
         <title><filename>meta/files/</filename></title>