In Windows 10 version 2004, we are introducing the concept of Hosted Apps to the Windows App Model. Hosted apps are registered as independent apps on Windows, but require a host process in order to run. An example would be a script file which requires its host (eg: Powershell or Python) to be installed. By itself, it is just a file and does not have any way to appear as an app to Windows. With the Hosted App Model, an app can declare itself as a host, and then packages can declare a dependency upon that host and are known as hosted apps. When the hosted app is launched, the host executable is then launched with the identity of the hosted app package instead of its own identity. This allows the host to be able to access the contents of the hosted app package and when calling APIs it does so with the hosted app identity.
This seems like something that could be useful for progressive web apps, and maybe even Electron apps by making them use Edge Chromium’s rendering engine instead of having every Electron application use its own copy of Chromium, which could benefit performance and battery life.