cdnjs is a free distributed JS library delivery service.
Firebase is a Google-backed application development software that enables developers to develop iOS, Android and Web apps.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
MathJax is a cross-browser JavaScript library that displays mathematical notation in web browsers, using MathML, LaTeX and ASCIIMathML markup.
WordPress is a free and open-source content management system written in PHP and paired with a MySQL or MariaDB database. Features include a plugin architecture and a template system.