cdnjs is a free distributed JS library delivery service.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
LiteSpeed is a high-scalability web server.
RequireJS is a JavaScript library and file loader which manages the dependencies between JavaScript files and in modular programming.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.