qmlplugindumper does not handle cross module dependencies triggered by composite types.
Composite types are really a qml file, and can import other modules.
The dependencies should be loaded with the builtins, so that the composite type dumper stops the merging of the prototype chain at the first type in the imported modules.
This will preserve the prototype chains across modules, and for example correctly find that ApplicationWindows inherits from QtQuick.Window, which currently requires hand editing.

The dependencies should also be listed in the qmltypes, to that the loader knows which libraries also have to be loaded.

One could discuss if imports containing Private should be treated as dependency, or directly linked.

This change will require creating extra qmltypes files for things like QtQuick.Controls.Layout, QtQuick.Controls.Styles,...