type og_type = | Website| Article| Profile
type og_property = | Title of string| Description of string| Image of Uri.t| Type of og_type
type robots_directive = | Index| Noindex| Follow| Nofollow| Noarchive
type t = | Charset of string| Viewport of string| Theme_color of string| Title of string| Description of string| Canonical_link of Uri.t| Robots of robots_directive list| Open_graph of og_property| Custom of {name : string;content : string;
}
val string_of_og_type : og_type -> stringval render_open_graph : og_property -> [> Html_types.meta ] Tyxml_html.eltval render : t -> [> `Link | `Meta | `Title ] Tyxml_html.elt