VirtualKeyboard not working under WebAssembly

cmake_minimum_required(VERSION 3.16)

project(vkbtest VERSION 0.1 LANGUAGES CXX)

set(CMAKE_AUTOMOC ON)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Qt6 6.4 COMPONENTS Quick REQUIRED)

qt_add_executable(appvkbtest
    main.cpp
)

qt_add_qml_module(appvkbtest
    URI vkbtest
    VERSION 1.0
    QML_FILES main.qml
)

target_compile_definitions(appvkbtest
    PRIVATE $<$<OR:$<CONFIG:Debug>,$<CONFIG:RelWithDebInfo>>:QT_QML_DEBUG>)
target_link_libraries(appvkbtest
    PRIVATE Qt6::Quick)

#include <QGuiApplication>
#include <QQmlApplicationEngine>


int main(int argc, char *argv[])
{
    qputenv("QT_IM_MODULE", QByteArray("qtvirtualkeyboard"));
    
    QGuiApplication app(argc, argv);
    
    QQmlApplicationEngine engine;
    const QUrl url(u"qrc:/vkbtest/main.qml"_qs);
    QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                     &app, [url](QObject *obj, const QUrl &objUrl) {
        if (!obj && url == objUrl)
            QCoreApplication::exit(-1);
    }, Qt::QueuedConnection);
    engine.load(url);
    
    return app.exec();
}
 

 import QtQuick 
import QtQuick.VirtualKeyboard

Window {
    id: window
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")
    
    InputPanel {
        id: inputPanel
        z: 99
        x: 0
        y: window.height
        width: window.width
        
        states: State {
            name: "visible"
            when: inputPanel.active
            PropertyChanges {
                target: inputPanel
                y: window.height - inputPanel.height
            }
        }
        transitions: Transition {
            from: ""
            to: "visible"
            reversible: true
            ParallelAnimation {
                NumberAnimation {
                    properties: "y"
                    duration: 250
                    easing.type: Easing.InOutQuad
                }
            }
        }
    }
}

find_package(Qt6 COMPONENTS Quick VirtualKeyboard REQUIRED) 
target_link_libraries(appvkbtest PRIVATE Qt6::Quick Qt6::VirtualKeyboard)

QQmlApplicationEngine failed to load component
qtloader.js:382 qrc:/vkbtest/main.qml:11:5: Type InputPanel unavailable
qtloader.js:382 qrc:/QtQuick/VirtualKeyboard/content/InputPanel.qml:131:5: Type Keyboard unavailable
qtloader.js:382 qrc:/QtQuick/VirtualKeyboard/content/components/Keyboard.qml:38:1: module "QtQuick.VirtualKeyboard.Plugins" is not installed

17:02:34: Running steps for project vkbtest...
17:02:34: Starting: "C:\Development\Qt\Tools\CMake_64\bin\cmake.exe" --build D:/code/vkbtest/build-vkbtest-WebAssembly_Qt_6_4_0-Debug --target all
jom: parallel job execution disabled for Makefile
[  5%] Built target appvkbtest_tooling
[ 11%] Generating .rcc/qmlcache/appvkbtest_qmlcache_loader.cpp
[ 16%] Automatic MOC for target appvkbtest
[ 16%] Built target appvkbtest_autogen
[ 22%] Running AUTOMOC file extraction for target appvkbtest
[ 22%] Built target appvkbtest_automoc_json_extraction
[ 33%] Running moc --collect-json for target appvkbtest
[ 33%] Running rcc for resource appvkbtest_raw_qml_0
[ 38%] Running rcc for resource qmake_vkbtest
[ 44%] Automatic QML type registration for target appvkbtest
[ 50%] Generating .rcc/qmlcache/appvkbtest_main_qml.cpp
Consolidate compiler generated dependencies of target appvkbtest
[ 55%] Building CXX object CMakeFiles/appvkbtest.dir/appvkbtest_autogen/mocs_compilation.cpp.o
[ 66%] Building CXX object CMakeFiles/appvkbtest.dir/.rcc/qrc_qmake_vkbtest.cpp.o
[ 66%] Building CXX object CMakeFiles/appvkbtest.dir/main.cpp.o
[ 77%] Building CXX object CMakeFiles/appvkbtest.dir/.rcc/qmlcache/appvkbtest_qmlcache_loader.cpp.o
[ 77%] Building CXX object CMakeFiles/appvkbtest.dir/.rcc/qrc_appvkbtest_raw_qml_0.cpp.o
[ 88%] Building CXX object CMakeFiles/appvkbtest.dir/.rcc/qmlcache/appvkbtest_main_qml.cpp.o
[ 88%] Building CXX object CMakeFiles/appvkbtest.dir/appvkbtest_qmltyperegistrations.cpp.o
[ 94%] Linking CXX executable appvkbtest.js
error: undefined symbol: _Z53qt_static_plugin_QtQuick_VirtualKeyboard_StylesPluginv (referenced by top-level compiled C/C++ code)
warning: Link with `-s LLD_REPORT_UNDEFINED` to get more information on undefined symbols
warning: To disable errors for undefined symbols use `-s ERROR_ON_UNDEFINED_SYMBOLS=0`
warning: __Z53qt_static_plugin_QtQuick_VirtualKeyboard_StylesPluginv may need to be added to EXPORTED_FUNCTIONS if it arrives from a system library
error: undefined symbol: _Z61qt_static_plugin_QtQuick_VirtualKeyboard_Styles_BuiltinPluginv (referenced by top-level compiled C/C++ code)
warning: __Z61qt_static_plugin_QtQuick_VirtualKeyboard_Styles_BuiltinPluginv may need to be added to EXPORTED_FUNCTIONS if it arrives from a system library
Error: Aborting compilation due to previous errors
em++: error: 'C:/Development/emscripten/emsdk/node/14.18.2_64bit/bin/node.exe C:\Development\emscripten\emsdk\upstream\emscripten\src\compiler.js C:\Users\chris\AppData\Local\Temp\tmpvstp4zw8.json' failed (returned 1)
jom: D:\code\vkbtest\build-vkbtest-WebAssembly_Qt_6_4_0-Debug\CMakeFiles\appvkbtest.dir\build.make [appvkbtest.js] Error 1
jom: D:\code\vkbtest\build-vkbtest-WebAssembly_Qt_6_4_0-Debug\CMakeFiles\Makefile2 [CMakeFiles\appvkbtest.dir\all] Error 2
jom: D:\code\vkbtest\build-vkbtest-WebAssembly_Qt_6_4_0-Debug\Makefile [all] Error 2
17:02:42: The process "C:\Development\Qt\Tools\CMake_64\bin\cmake.exe" exited with code 2.
Error while building/deploying project vkbtest (kit: WebAssembly Qt 6.4.0)
The kit WebAssembly Qt 6.4.0 has configuration issues which might be the root cause for this problem.
When executing step "Build"
17:02:42: Elapsed time: 00:08.