<document source="test data">
    <paragraph>
        Duplicate implicit/explicit targets.
    <section dupnames="title" ids="title">
        <title>
            Title
        <system_message backrefs="id1" level="1" line="6" source="test data" type="INFO">
            <paragraph>
                Duplicate explicit target name: "title".
        <target ids="id1" names="title">
        <paragraph>
            Paragraph.
