Apache is a free and open-source cross-platform web server software.
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.
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.
Unpkg is a content delivery network for everything on npm.