The source provides an exhaustive technical and historical overview of the Web View Transition API, a modern set of web platform features designed to enable fluid, animated transitions between user interface states, making web applications feel more like native applications. It details the core mechanics of same-document transitions (for single-page apps), which use CSS pseudo-elements and snapshots of the DOM to perform compositor-accelerated animations without relying on manual JavaScript. Furthermore, the text explores advanced features like cross-document transitions (for multi-page navigations) and the emerging element-scoped transitions, which allow for concurrent, localized animations within specific parts of a page. Finally, the source documents the feature's evolution through the standards process, highlighting key contributors, security considerations (like same-origin enforcement), and the intricate internal implementation within the Chromium (Blink) rendering engine.
