Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
Contao is an open source CMS that allows you to create websites and scalable web applications.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Leaflet is the open-source JavaScript library for mobile-friendly interactive maps.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Unpkg is a content delivery network for everything on npm.