Apache is a free and open-source cross-platform web server software.
Backdrop is an open-source content management system (CMS) derived from Drupal 7, offering a user-friendly interface, customisable content types, taxonomies, views, theming capabilities, extensibility through modules, and regular security updates.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.