See http://lists.forgerock.org/pipermail/opendj/2012-March/001504.html

Mark Craig

06.45.2012 6a293f9143c13f2769eb8b9595dbd2f33ae6b737

 opendj3/src/main/docbkx/admin-guide/chap-indexing.xml

@@ -741,5 +741,12 @@
    </tbody>
   </tgroup>
  </table>

  <para>When you create a JE backend using the <command>dsconfig</command>
  command, OpenDJ creates the <literal>aci</literal> presence,
  <literal>ds-sync-conflict</literal> equality,
  <literal>ds-sync-hist</literal> ordering,
  <literal>entryUUID</literal> equality, and
  <literal>objectClass</literal> equality indexes automatically.</para>
 </section>
</chapter>