Ahrefs is an online toolset utilised for search engine optimisation (SEO) and competitor analysis, which permits users to analyse their website's performance, track keyword rankings, identify backlink opportunities, and research competitors' websites, among other features.
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.
Vercel is a cloud platform for static frontends and serverless functions.