diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 958d2feb15..d5ca11b2a7 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -2906,6 +2906,27 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-PACKAGE_INSTALL'><glossterm>PACKAGE_INSTALL</glossterm>
+            <glossdef>
+                <para>
+                    The final list of packages passed to the package manager
+                    for installation into the image.
+                    Because the package manager controls actual installation
+                    of all packages, the list of packages passed using
+                    <filename>PACKAGE_INSTALL</filename> is not the final list
+                    of packages that are actually installed.
+                </para>
+
+                <para>
+                    This variable is internal to the image construction
+                    code.
+                    Use the
+                    <link linkend='var-IMAGE_INSTALL'><filename>IMAGE_INSTALL</filename></link>
+                    variable to specify packages for installation.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-PACKAGECONFIG'><glossterm>PACKAGECONFIG</glossterm>
             <glossdef>
                 <para>