+ <para>If a unit file is empty (i.e. has the file size
+ 0) or is symlinked to <filename>/dev/null</filename>
+ its configuration will not be loaded and it appears
+ with a load state of <literal>masked</literal>, and
+ cannot be activated. Use this as an effective way to
+ fully disable a unit, making it impossible to start it
+ even manually.</para>
+