jenkins/war/resources/help/security/ldap/groupSearchBase.html

<div>
    One of the searches Hudson does on LDAP is to locate the list of groups for a user.

    <p>
    This field determines the query to be run to identify the organizational unit that contains groups. The query is
    almost always <tt>"ou=groups"</tt>, so in most cases you should leave this field empty and let this default kick in.

</div>