For documents like PDFs, there’s no way to position canonical tags in the webpage header for the reason that there is not any web site section. In these kinds of cases, you’ll ought to use HTTP headers to set canonicals. What this means is other rating variables may possibly override https://addons.prestashop.com/fr/seo-referencement-naturel/31857-seo-automatique-google-rich-snippets-json-ld-open-graph.html