diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 98557f0a79..3088123581 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -120,6 +120,39 @@
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-BB_DANGLINGAPPENDS_WARNONLY'><glossterm>BB_DANGLINGAPPENDS_WARNONLY</glossterm>
+            <glossdef>
+                <para>
+                    Defines how BitBake handles situations where an append
+                    file (<filename>.bbappend</filename>) has no
+                    corresponding recipe file (<filename>.bb</filename>).
+                    This condition often occurs when layers get out of sync
+                    (e.g. <filename>oe-core</filename> bumps a
+                    recipe version and the old recipe no longer exists and the
+                    other layer has not been updated to the new version
+                    of the recipe yet).
+                </para>
+
+                <para>
+                    The default fatal behavior is safest because it is
+                    the sane reaction given something is out of sync.
+                    It is important to realize when your changes are no longer
+                    being applied.
+                </para>
+
+                <para>
+                    You can change the default behavior by setting this
+                    variable to "1" in the <filename>local.conf</filename>
+                    file in the
+                    <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
+                    as follows:
+                    <literallayout class='monospaced'>
+     BB_DANGLINGAPPENDS_WARNONLY = "1"
+                    </literallayout>
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-BB_DISKMON_DIRS'><glossterm>BB_DISKMON_DIRS</glossterm>
             <glossdef>
                 <para>