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.
MODX (originally MODx) is an open source content management system and web application framework for publishing content on the World Wide Web and intranets.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.