Firebase is a Google-backed application development software that enables developers to develop iOS, Android and Web apps.
Full Featured Mobile HTML Framework For Building iOS & Android Apps.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
JSDelivr is a free public CDN for open-source projects. It can serve web files directly from the npm registry and GitHub repositories without any configuration.
Open Graph is a protocol that is used to integrate any web page into the social graph.