# Activity web publication manifest extension ```https://id.openeel.org/extensions/activity/webpub-manifest-link``` A [WebPub Manifest](https://readium.org/webpub-manifest/) can represent how a collection of resources can be grouped together to represent a publication (see also [W3C Web Publications](https://w3c.github.io/dpub-pwp-ucr/)). A publication manifest can also include a manifest listing all the resources required, enabling such resources to be cached for future use offline. An activity can use this extension as follows: ``` { "id":"https://example.com/xapi/activity", "definition":{ "name":{ "en-US":"An activity" }, "extensions": { "https://id.openeel.org/extensions/activity/webpub-manifest-link": "https://example.com/xapi/activity/manifest.json" } } } ```