cdnjs is a free distributed JS library delivery service.
Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web.
Modernizr is a JavaScript library that detects the features available in a user's browser.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.