Allows websites to register offline enabled content in the browser. This allows the browser to improve the offline experience and allow content browsing when the user is offline. This data could also be used to improve on-device search and to augment browsing history.
Unreliable or even unavailable network connections are very common on mobile devices. This API allows browsers to show meaningful content to users in these situations and enables sites to increase user engagement. Browser vendors are already looking for content relevant to the user based on their browsing history and make it available to be consumed offline. This is not ideal as it ignores the entity with the most knowledge of that content: the providers themselves. With this API content providers can highlight user specific, high quality content through the browser. Grouping content by a category (e.g. 'article', 'video', 'audio') allows an even richer experience as the browser is able to understand what kind of content is available and show a relevant UI.
Docs: https://web.dev/content-indexing-api/
Samples: https://github.com/GoogleChrome/samples/tree/gh-pages/web-share https://contentindex.dev/
Explainers: https://github.com/wicg/content-index https://docs.google.com/document/d/10oZSVvpMvnf3Bd2amz-jywLA1D25pcEMpbSmlom1MVk/