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.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Headroom.js is a JS widget that allows you to react to the user's scroll. The header slides out of view when scrolling down and slides back in when scrolling up.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.