ref-manual: add PACKAGE_ADD_METADATA documentation

Add a basic variable definition and a small section to the development
tasks manual for using PACKAGE_ADD_METADATA to add custom metadata to
packages.

(From yocto-docs rev: c5e4d575a771ddd1c970389ce3ace6d6abe68769)

Signed-off-by: Michael Ho <Michael.Ho@bmw.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 34 insertions, 0 deletions

diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 364cd09eb8..657f6cf3d2 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -9539,6 +9539,40 @@
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-PACKAGE_ADD_METADATA'><glossterm>PACKAGE_ADD_METADATA</glossterm>
+            <info>
+                PACKAGE_ADD_METADATA[doc] = "This variable defines additional metadata to add to packages."
+            </info>
+            <glossdef>
+                <para role="glossdeffirst">
+<!--                <para role="glossdeffirst"><imagedata fileref="figures/define-generic.png" /> -->
+                    This variable defines additional metdata to add to packages.
+                </para>
+
+                <para>
+                    You may find you need to inject additional metadata into
+                    packages. This variable allows you to do that by setting
+                    the injected data as the value. Multiple fields can be
+                    added by splitting the content with the literal separator
+                    "\n".
+                </para>
+
+                <para>
+                    The suffixes '_IPK', '_DEB', or '_RPM' can be applied to
+                    the variable to do package type specific settings. It can
+                    also be made package specific by using the package name as
+                    a suffix.
+                </para>
+
+                <para>
+                    You can find out more about applying this variable in
+                    the
+                    "<ulink url='&YOCTO_DOCS_DEV_URL;#adding-custom-metadata-to-packages'>Adding custom metadata to packages</ulink>"
+                    section in the Yocto Project Development Tasks Manual.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-PACKAGE_ARCH'><glossterm>PACKAGE_ARCH</glossterm>
             <info>
                 PACKAGE_ARCH[doc] = "The architecture of the resulting package or packages."