Apache is a free and open-source cross-platform web server software.
cdnjs is a free distributed JS library delivery service.
Google Maps is a web mapping service. It offers satellite imagery, aerial photography, street maps, 360° interactive panoramic views of streets, real-time traffic conditions, and route planning for traveling by foot, car, bicycle and air, or public transportation.
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.
Leaflet is the open-source JavaScript library for mobile-friendly interactive maps.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
Unpkg is a content delivery network for everything on npm.