Donorbox is a US-based technology company. It offers an online fundraising software that allows individuals and nonprofit organisations to receive donations over the Internet.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
OneSignal is a customer engagement messaging solution.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
W3 Total Cache (W3TC) improves the SEO and increases website performance and reducing load times by leveraging features like content delivery network (CDN) integration and the latest best practices.