diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 16f972ce37..e712d9d64a 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -1465,6 +1465,21 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-KBRANCH_DEFAULT'><glossterm>KBRANCH_DEFAULT</glossterm>
+            <glossdef>
+                <para>
+                    Defines the Linux kernel source repository's default
+                    branch used to build the Linux kernel.
+                    The <filename>KBRANCH_DEFAULT</filename> value is
+                    the default value for
+                    <link linkend='var-KBRANCH'><filename>KBRANCH</filename></link>.
+                    Unless you specify otherwise,
+                    <filename>KBRANCH_DEFAULT</filename> initializes to
+                    "master".
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-KERNEL_FEATURES'><glossterm>KERNEL_FEATURES</glossterm>
             <glossdef>
                 <para>Includes additional metadata from the Yocto Project kernel Git repository.