This repository is the official W3C WebSub specification (formerly PubSubHubbub), a decentralized publish/subscribe protocol over HTTP. It is not a software application or data pipeline; it contains the normative ReSpec specification documents, implementation reports, and W3C governance metadata. The core deliverable is source.html, with staged snapshots for FPWD, Working Draft, and the 2018 Recommendation. The spec defines three roles — publisher, subscriber, and hub — and specifies discovery via link rel=hub/self, hub subscription/unsubscription with lease management, content distribution via POST, and optional authenticated distribution using HMAC signatures. It also includes conformance classes and implementation report templates that multiple independent projects (Google, Mastodon, Twitch, Superfeedr, etc.) have used to self-certify interoperability.