These are things that may be addressed in future revisions:
Enable the creation of instant articles quickly. This includes, among other things, support for instant article items in the headers.
<meta property="op:markup_version" content="v1.0">
<meta property="fb:article_style" content="myarticlestyle">Enable Twitter Cards for a given page and/or the site in general.
<meta name="twitter:card" content="summary">
<meta name="twitter:site" content="@site_account">
<meta name="twitter:creator" content="@individual_account">
<meta name="twitter:url" content="https://example.com/page.html">
<meta name="twitter:title" content="Content Title">
<meta name="twitter:description" content="Content description less than 200 characters">
<meta name="twitter:image" content="https://example.com/image.jpg"><link href="https://plus.google.com/+YourPage" rel="publisher">
<meta itemprop="name" content="Content Title">
<meta itemprop="description" content="Content description less than 200 characters">
<meta itemprop="image" content="https://example.com/image.jpg">