<https://wpcustoms.net/snippets/add-custom-post-types-to-your-feed/#breadcrumb>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://schema.org/BreadcrumbList>
<https://wpcustoms.net/snippets/add-custom-post-types-to-your-feed/>