diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 89970421ad..9d53fea0f3 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -9297,6 +9297,18 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
                     for more than one package in <filename>PACKAGES</filename>,
                     it will be assigned to the earliest (leftmost) package.
                 </para>
+
+                <para>
+                    Packages in the variable's list that are empty (i.e. where
+                    none of the patterns in
+                    <filename>FILES_</filename><replaceable>pkg</replaceable>
+                    match any files installed by the
+                    <link linkend='ref-tasks-install'><filename>do_install</filename></link>
+                    task) are not generated, unless generation is forced through
+                    the
+                    <link linkend='var-ALLOW_EMPTY'><filename>ALLOW_EMPTY</filename></link>
+                    variable.
+                </para>
             </glossdef>
         </glossentry>