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.
Naver Analytics is a Korean based analytics service.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
Unpkg is a content delivery network for everything on npm.
Vercel is a cloud platform for static frontends and serverless functions.