returns property

The PluginResult class this action hands back, when it hands back data.

A Type rather than a name, because that is what can be followed: the capability document resolves this literal statically and walks the class's fields, so the published shape of a result is the class itself and cannot drift from it. A string would document a promise nothing could check.

It is also checked at run time — an action that declares one and returns something else fails the way any other broken invocation does, rather than quietly publishing a shape it does not produce.

Null for an action that returns nothing, or a scalar.