MetaExtensions like twitter:app:name: are used by Twitter Card but are not defined


I generated a twitter card for my website and the resulting meta tags included both “twitter:app:id:” tags and “twitter:app:name:” tags. However I noticed that the W3C validator doesn’t like the “twitter:app:name:” tags, and looking at the page I see that they are not infact defined, only the “twitter:app:id:” namespaces are defined.

Looking at the documentation at, I see that among the suggested meta tags are only the “twitter:app:id:” tags, and not the “twitter:app:name:” tags.

Are the “twitter:app:name:” tags useful? And if so, should I update the page with them? And if so, perhaps also the page should be updated also…