Building the filesystemexplorer example from qtdeclarative/examples/quickcontrols against dev works, but starting the bundle via open filesystemexplorerapp does not start the application.

Launching the executable directly produces

$ ./filesystemexplorerapp.app/Contents/MacOS/filesystemexplorerapp
QQmlApplicationEngine failed to load component
<Unknown File>: Module "FileSystemModule" contains no type named "Main"

The FileSystemModule is present in the build tree, but it's not inside the bundle. Copying it explicitly next to the executable makes things work.

Since the module belongs to the executable and is added for the executable target via

qt_add_qml_module(filesystemexplorerapp
    URI FileSystemModule

in the CMakeLists.txt file, this should just work.