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.
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.
Matter.js is a 2D physics engine for the web. It provides JavaScript-based tools for simulating rigid body physics in 2D environments.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.