Its not a new feature, so you can build pluggable using source and listening. I Wich!
The update handing inside widgets works different for pluggable widgets the dojo widgets. So a data view that listens to a data source was not possible to use in side a pluggable widget. Normal data view where already supported.
Before 8.11 you will get a message CE6700 Widget <pluggable widget> '<name>' cannot contain widgets of type data view when your data view, inside a pluggable widget, is listening to a data source.
So no big feature, but it making the pluggable widget more compatible
My guess is that they are referring to the functionality for data views to listen to a selection made by a list/grid. This has been available for quite some time but it was probably not compatible with the whole pluggable architecture.
That is it was not compatible until now.