This enables PWAs on the upcoming Windows Release (builds greater than 19022) to appear to the Shell more like a native app would. For example, that post I responded to earlier today wanted notifications to say "whatsapp" instead of "microsoft edge", this feature enables that. It will also allow the app to be uninstalled more easily, show up in task-manager under its own name, and some other features. In the future, apps should then get badges and unique jumplists as well.
We are behind on our documentation of this feature work, my apologies for that.