A customer with a static version of Qt 6.3.0 got this:

LINK : fatal error LNK1181: Input file "runtimeobject.lib.lib" cannot be opened.
LINK : fatal error LNK1181: Input file "user32.lib.lib" cannot be opened.

This is probably due to the following section in <QT>\qtconnectivity\src\bluetooth\CMakeLists.txt:

qt_internal_extend_target(Bluetooth
    PUBLIC_LIBRARIES
        Qt::Core
        runtimeobject.lib
        user32.lib
)

All other CMakeLists.txt files in in Qt 6.3.0 use "user32", not "user32.lib".

Note: A quick search reveals multiple uses of "runtimeobject.lib" instead of "runtimeobject":

• <QT>\qtconnectivity\config.tests\winrt_bt\CMakeLists.txt
• <QT>\qtconnectivity\src\bluetooth\CMakeLists.txt
• <QT>\qtlocation\config.tests\winrt\CMakeLists.txt
• <QT>\qtlocation\src\plugins\position\winrt\CMakeLists.txt
• <QT>\qtpositioning\config.tests\winrt\CMakeLists.txt
• <QT>\qtpositioning\src\plugins\position\winrt\CMakeLists.txt
• <QT>\qtsensors\config.tests\winrt\CMakeLists.txt
• <QT>\qtsensors\src\plugins\sensors\winrt\CMakeLists.txt