AMP, originally created by Google, is an open-source HTML framework developed by the AMP open-source Project. AMP is designed to help webpages load faster.
cdnjs is a free distributed JS library delivery service.
Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.
Mailchimp is a marketing automation platform and email marketing service.
PHP is a general-purpose scripting language used for web development.