Qt for Python (PySide/Shiboken)

https://www.qt.io/blog/qml-type-registration-in-qt-5.15 From Ulf Hermann. An excerpt that relates to what I'm talking about: Furthermore, as you register your types procedurally, any QML tooling cannot automatically tell which types are available in which import. Qt Creator indeed has some heuristics that try to detect common registration patterns in C++ code, but this is necessarily incomplete. Figuring out whether a specific registration will be executed by the program is equivalent to solving the halting problem. Simpler tools like qmllint or qmlformat have no information about the C++ code and need to analyze your QML code in isolation. Therefore, they won't have any information about types registered from C++. In order to (partially) solve this problem the "qmltypes" files were introduced.