HTTP/2
The second major version of HTTP that loads web pages faster by sending many requests over one connection at the same time, replacing HTTP/1.1's one-request-at-a-time model.
Full Definition
HTTP/2 is the second major revision of the HTTP protocol, standardised in 2015. Its key features are multiplexing (sending multiple requests and responses over a single TCP connection simultaneously), header compression (HPACK), and server push. For anti-bot systems, HTTP/2 introduces a new fingerprinting surface: the order of pseudo-headers (like :method, :path, :scheme, :authority), SETTINGS frame values, and window update sizes are unique to different browser implementations. A scraper using Python's requests library (which speaks HTTP/1.1) can be fingerprinted for this, as it doesn't match the HTTP/2 fingerprint of real Chrome or Firefox.
