Apache is a free and open-source cross-platform web server software.
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.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.