HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Ko-fi is an online platform that helps content creators get the financial support.
Open Graph is a protocol that is used to integrate any web page into the social graph.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.