The document discusses HTTP/3, which is built on QUIC, a protocol developed by Google to improve performance and security over existing HTTP/1 and HTTP/2. It highlights the benefits of HTTP/3, including faster handshakes, independent streams, and always-on encryption, while also addressing challenges such as client fallback and CPU-intensive implementations. The document provides implementation status updates and anticipates a gradual adoption of HTTP/3 due to challenges in transitioning from HTTP/2.