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.
cdnjs is a free distributed JS library delivery service.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Netlify providers hosting and server-less backend services for web applications and static websites.