You can define AppStreams/modules that are parallel installable. Indeed, that's how the Python AppStreams are set up right now. However, the default way an App

You can define AppStreams/modules that are parallel installable. Indeed, that's how the Python AppStreams are set up right now. However, the default way an AppStream is made eschews parallel installation support. Red Hat will make parallel-installable AppStreams whenever it is needed. And they can incorporate the content of one AppStream in another if need be.