This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
data property returns an arbitrary object representing any data passed with the activity.
var options = instanceOfMozActivityOptions.data
Return an object.
If no data are necessary, this property can be
Web Activities is not part of any specification. However, it has some overlap with the proposed Web Intents specification. Mozilla actually proposed Web Activities as a counter proposal to Web Intents. For more information about this, see discussion on the Web Intents Task Force ML.