{crmScope extensionKey='dataprocessor'}
<div class="crm-section">
    <div class="label">{ts}Join on field{/ts} <span class="marker">*</span></div>
    <div class="content">
                    {$form.left_field.html}
                    &nbsp;=&nbsp;
                    {$form.right_field.html}
    </div>
</div>
{/crmScope}