app/bundles/DynamicContentBundle/Resources/views/SubscribedEvents/Timeline/index.html.twig

{% set data = event.extra.stat.sentDetails %}

{% if data.failed is not defined and data.timeline is defined %}
    <dl class="dl-horizontal">
        <dt>{{ 'mautic.dynamicContent.timeline.content'|trans }}</dt>
        <dd>{{ data.timeline|trans }}</dd>
    </dl>
{% endif %}