The 'event' endpoint allows publishing an xApp event in the "Requests" event list of a user, while sending a Push notification pointing to the event.
xApps are embedded apps. Publishing and xApp and calling xApp API endpoints are only available for XRPL Labs / XUMM partners.
The data in the data property will be returned as origin.data in the xapp/ott/:token
The user_token can be obtained by requesting the user to sign a User Sign In payload using the regular payload method.
When you want to remove the Event from the Requests tab (eg. because the user tapped the push notification and resolved the request) use the payload/:payload_uuid method. Use the returned uuid (payload UUID).