diff --git a/doc/xmllint.xml b/doc/xmllint.xml
index bd87e9b62..1901e89be 100644
--- a/doc/xmllint.xml
+++ b/doc/xmllint.xml
@@ -576,6 +576,8 @@
                     node set is serialized in full in the output. In case
                     of an empty node set the "XPath set is empty" result
                     will be shown unless the <option>--quiet</option> is set.
+                    This feature is EXPERIMENTAL. Implementation details can
+                    change without futher notice.
                 </para>
             </listitem>
         </varlistentry>