Apache is a free and open-source cross-platform web server software.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
PHP is a general-purpose scripting language used for web development.
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.
Tippy.js is the complete tooltip, popover, dropdown, and menu solution for the web, powered by Popper.
Unpkg is a content delivery network for everything on npm.