What Is HTTP/3 – Lowdown on the Fast New UDP-Based Protocol
HTTP/3 builds on User Datagram Protocol (UDP), and is already being used by prominent internet companies such as Google and Facebook. If you’re using Chrome and connecting to a Google service, you’re probably already using QUIC.
Source: What Is HTTP/3 - Lowdown on the Fast New UDP-Based Protocol, an article by Tonino Jankov.