<https://support.metabox.io/topic/custom-post-not-showing-on-the-front-end-but-are-working-through-wpgridbuilder#breadcrumbs>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://support.metabox.io/topic/custom-post-not-showing-on-the-front-end-but-are-working-through-wpgridbuilder/>