#find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Widgets)
#find_package(QT NAMES Qt6 REQUIRED COMPONENTS Widgets)
find_package(QT NAMES Qt5 REQUIRED COMPONENTS Widgets)

The first and third line result in a Qt5 build. The second line results in a Qt6 build. The "Qt version" field in my kit seems to have no influence. I set the value to "None".

The issue is resolved. However in a weird way.

Is there a way to insert a code segment without automatic coloring?

```text
your log
```

First cmake:

markus@ryzen ~/Qt/Projekt_Muehle $ cmake -G Ninja -S Qt/ -B Qt/build/test_build/
-- The CXX compiler identification is GNU 15.2.1
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done (0.2s)
-- Generating done (0.0s)
-- Build files have been written to: /home/markus/Qt/Projekt_Muehle/Qt/build/test_build

Then ninja:

markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ ls
build.ninja  CMakeCache.txt  CMakeFiles  cmake_install.cmake
markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ ninja
[13/13] Linking CXX executable Projekt_Muehle

The files build.ninja and CMakeCache.txt only contain references to Qt 5:

markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ grep LINK_LIBRARIES build.ninja
  LINK_LIBRARIES = /usr/lib64/libQt5Widgets.so.5.15.18  /usr/lib64/libQt5Gui.so.5.15.18  /usr/lib64/libQt5Core.so.5.15.18
markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ grep -e Qt5Widgets -e Qt5Gui -e Qt5Core CMakeCache.txt
//The directory containing a CMake configuration file for Qt5Core.
Qt5Core_DIR:PATH=/usr/lib64/cmake/Qt5Core
//The directory containing a CMake configuration file for Qt5Gui.
Qt5Gui_DIR:PATH=/usr/lib64/cmake/Qt5Gui
//The directory containing a CMake configuration file for Qt5Widgets.
Qt5Widgets_DIR:PATH=/usr/lib64/cmake/Qt5Widgets
markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ grep -e Qt6Widgets -e Qt6Gui -e Qt6Core CMakeCache.txt

These two files were generated by Qt Creator prior to me using the command line:

markus@ryzen ~/Qt/Projekt_Muehle/Qt $ ls CMakeLists.txt .qtcreator/CMakeLists.txt.user 
CMakeLists.txt  .qtcreator/CMakeLists.txt.user

I don't think the second file is relevant for the command line cmake.

Just to clear things out, can you properly build that project on the command line for each version of Qt ?

cmake_minimum_required(VERSION 3.16)

project(Projekt_Muehle VERSION 0.1 LANGUAGES CXX)

set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

#set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

include_directories(${PROJECT_SOURCE_DIR})

find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Widgets)
find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Widgets)

set(PROJECT_SOURCES
        main.cpp
        mainwindow.cpp
        mainwindow.h
        mainwindow.ui
)

if(${QT_VERSION_MAJOR} GREATER_EQUAL 6)
    qt_add_executable(Projekt_Muehle
        MANUAL_FINALIZATION
        ${PROJECT_SOURCES}
        add_args.h
        add_args.cpp
        mill_view.h mill_view.cpp
        mill_model.h mill_model.cpp
        mill_controller.h mill_controller.cpp
        player.h player.cpp
        board.h board.cpp board.ui
        token.h token.cpp token.ui
        board_label.h board_label.cpp board_label.ui
        res.qrc
    )
# Define target properties for Android with Qt 6 as:
#    set_property(TARGET Projekt_Muehle APPEND PROPERTY QT_ANDROID_PACKAGE_SOURCE_DIR
#                 ${CMAKE_CURRENT_SOURCE_DIR}/android)
# For more information, see https://doc.qt.io/qt-6/qt-add-executable.html#target-creation
else()
    if(ANDROID)
        add_library(Projekt_Muehle SHARED
            ${PROJECT_SOURCES}
        )
# Define properties for Android with Qt 5 after find_package() calls as:
#    set(ANDROID_PACKAGE_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/android")
    else()
        add_executable(Projekt_Muehle
            ${PROJECT_SOURCES}
            add_args.cpp add_args.h
            board.cpp board.h board.ui
            board_label.cpp board_label.h board_label.ui
            mill_controller.cpp mill_controller.h
            mill_model.cpp mill_model.h
            mill_view.cpp mill_view.h
            player.cpp player.h
            token.cpp token.h token.ui
        )
    endif()
endif()

target_link_libraries(Projekt_Muehle PRIVATE Qt${QT_VERSION_MAJOR}::Widgets)

# Qt for iOS sets MACOSX_BUNDLE_GUI_IDENTIFIER automatically since Qt 6.1.
# If you are developing for iOS or macOS you should consider setting an
# explicit, fixed bundle identifier manually though.
if(${QT_VERSION} VERSION_LESS 6.1.0)
  set(BUNDLE_ID_OPTION MACOSX_BUNDLE_GUI_IDENTIFIER com.example.Projekt_Muehle)
endif()
set_target_properties(Projekt_Muehle PROPERTIES
    ${BUNDLE_ID_OPTION}
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
    MACOSX_BUNDLE TRUE
    WIN32_EXECUTABLE TRUE
)

include(GNUInstallDirs)
install(TARGETS Projekt_Muehle
    BUNDLE DESTINATION .
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

if(QT_VERSION_MAJOR EQUAL 6)
    qt_finalize_executable(Projekt_Muehle)
endif()

So did you fetch and install (a pre-built) Qt6 yourself? Is your kit and build commands not picking that up and compiling/linking against the system's Qt5?