HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
IPInfoDB is the API that returns the location of an IP address.
MaxMind is a provider of geolocation and online fraud detection tools.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.