diff --git a/man/systemd-debug-generator.xml b/man/systemd-debug-generator.xml
index af3615175e5..126d1efc002 100644
--- a/man/systemd-debug-generator.xml
+++ b/man/systemd-debug-generator.xml
@@ -80,7 +80,8 @@
         <listitem><para>Credentials prefixed with <literal>systemd.extra-unit.</literal> specify additional
         units to add to the final system. Note that these additional units are added to both the initrd and
         the final system. <varname>ConditionPathExists=!/etc/initrd-release</varname> can be used to make
-        sure the unit is conditioned out in the initrd.</para>
+        sure the unit is conditioned out in the initrd. Note that this can also be used to mask units, by
+        simply specifying an empty value.</para>
 
         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
       </varlistentry>