_includes/head/seo/twitter.html

    <meta name="twitter:card" content="{{ site.seo.twitter.card_type }}"/>
    <meta name="twitter:image" content="{{ seo_image }}"/>
    <meta name="twitter:title" content="{{ seo_title }}"/>
    <meta name="twitter:description" content="{{ seo_description }}"/>
    <meta name="twitter:site" content="@{{ site.seo.twitter.username }}"/>