According to https://developers.google.com/search/docs/advanced/crawling/localized-versions?hl=fr#language-codes The hreflang attribute in the following lines should be in format ISO 639-1 : https://github.com/Novactive/Nova-eZPlatform-Bundles/blob/master/components/SEOBundle/bundle/Resources/views/seometas_metaslinks.html.twig#L39
According to https://developers.google.com/search/docs/advanced/crawling/localized-versions?hl=fr#language-codes
The hreflang attribute in the following lines should be in format ISO 639-1 : https://github.com/Novactive/Nova-eZPlatform-Bundles/blob/master/components/SEOBundle/bundle/Resources/views/seometas_metaslinks.html.twig#L39