The module automatically adds a default canonical url to all your merchandise, class, CMS pages only. By default, the module employs the current url of your webpage since the default canonical url. Yahoo: Yahoo makes use of Bing’s lookup technologies and supports hreflang tags in a similar way as Bing. https://addons.prestashop.com/en/seo-natural-search-engine-optimization/31857-automatic-google-rich-snippets-json-ld-open-graph-seo.html