HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
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.
Vercel is a cloud platform for static frontends and serverless functions.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.