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.
OpenLayers is an open-source JavaScript library for displaying map data in web browser.
PHP is a general-purpose scripting language used for web development.