HTTP (MDN)

1. HTTP guides
2. HTTP authentication
3. Browser detection using the user agent string (UA sniffing)
4. Cross-Origin Resource Sharing (CORS)
5. Content Security Policy (CSP)
6. HTTP caching
7. HTTP Client hints
8. Compression in HTTP
9. Compression Dictionary Transport
10. HTTP conditional requests
11. Connection management in HTTP/1.x
12. Content negotiation

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.