cdnjs is a free distributed JS library delivery service.
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.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Modernizr is a JavaScript library that detects the features available in a user's browser.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Optimizely is an experimentation platform that helps developers build and run A/B tests on websites.
Osano is a data privacy platform that helps your website become compliant with laws such as GDPR and CCPA.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
RequireJS is a JavaScript library and file loader which manages the dependencies between JavaScript files and in modular programming.
A modest JavaScript framework for the HTML you already have.