cdnjs is a free distributed JS library delivery service.
Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Analytics is a free web analytics service that tracks and reports website traffic.
jQuery CDN is a way to include jQuery in your website without actually downloading and keeping it your website's folder.
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.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
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.