diff --git a/man/systemd.xml b/man/systemd.xml
index 28bf49e131..8b1b6e6c6b 100644
--- a/man/systemd.xml
+++ b/man/systemd.xml
@@ -649,9 +649,17 @@
 
       <varlistentry>
         <term><varname>$SYSTEMD_UNIT_PATH</varname></term>
+        <term><varname>$SYSTEMD_GENERATOR_PATH</varname></term>
+        <term><varname>$SYSTEMD_ENVIRONMENT_GENERATOR_PATH</varname></term>
 
-        <listitem><para>Controls where systemd looks for unit
-        files.</para></listitem>
+        <listitem><para>Controls where systemd looks for unit files and
+        generators.</para>
+        <para>These variables may contain a list of paths, separated by colons
+        (<literal>:</literal>). When set, if the list ends with an empty
+        component (<literal>...:</literal>), this list is prepended to the
+        usual set of of paths. Otherwise, the specified list replaces the usual
+        set of paths.
+        </para></listitem>
       </varlistentry>
 
       <varlistentry>