<code>REMOTE_USER</code> to be set. The <var>varname</var> can be
any of the <a href="#envvars">SSL environment variables</a>.</p>
-<p>When the <code>FakeBasicAuth</code> option is enabled, this directive
-instead controls the value of the username embedded within the basic
-authentication header (see <a href="#ssloptions">SSLOptions</a>).</p>
+<p>When the <code>FakeBasicAuth</code> option (see
+<a href="#ssloptions">SSLOptions</a>) or the
+<directive module="mod_ssl">AuthBasicFake</directive> directive is in
+effect, this directive controls which part of the client certificate is
+used as the username. Without <directive>SSLUserName</directive>,
+<code>REMOTE_USER</code> may not be set for other modules and CGI scripts.</p>
<example><title>Example</title>
<highlight language="config">