This repository is the W3C WebTransport specification and its supporting reference materials. It is not a deployed application but a standards-track document repository with interactive sample code. The core deliverable is index.bs, a Bikeshed/WebIDL specification defining the WebTransport API for low-latency, bidirectional, client-server communication over QUIC/HTTP/3, with fallback to HTTP/2. The spec covers reliable streams, unreliable datagrams, send ordering/groups, atomic writes, connection stats, and security/privacy considerations. In practice, this repo defines an evolving browser API, not a runtime service. The repository also contains functional sample implementations: a basic JavaScript echo client and a more advanced WebCodecs echo sample that streams real-time video over WebTransport using a dedicated worker. The Python reference servers (samples/echo/py-server) implement a WebTransport-over-HTTP/3 endpoint using aioquic, handling CONNECT handshakes, bidirectional streams, unidirectional streams, and datagrams. These samples are the only executable code and serve as demonstration/test harnesses rather than production components. As a spec repository, the codebase is maintained and receives regular updates, but it is deliberately experimental. The API surface and underlying IETF drafts are still evolving, sample code references hardcoded public endpoints, and some bundled ReSpec infrastructure appears dated. The specification itself is carefully written and follows W3C conventions, but the repository's value is primarily as a normative reference and a source of patterns for WebTransport implementations.