Aruba.it is an Italian company mainly active in the web hosting and domain registration businesses.
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.
HTTP/3 is the third major version of the Hypertext Transfer Protocol used to exchange information on the World Wide Web.
PHP is a general-purpose scripting language used for web development.