Edit: Current situation is as described below, however now just for Qt WebAssembly
I am doing an in-source build of Qt 5.13 with MSVC 2017: configure... && jom. Until recently, the resulting Qt Quick modules in qt5/qtbase/qml/ were complete and fine.
Now, plugins.qmltypes and designer/* don't get copied into that place during the build, anymore. The result is that, although the modules are still functional when used at run time, the Qt Quick Designer cannot work with these modules anymore.
Did something change?