SUMMARY
I right-clicked on window decoration of System Settings, hovered over "More actions",
chose "Configure special application settings...", clicked on "Cancel" button
and System Settings crashed.

SOFTWARE/OS VERSIONS
Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.20.80
KDE Frameworks Version: 5.79.0
Qt Version: 5.15.2

Application: System Settings (systemsettings5), signal: Segmentation fault
Content of s_kcrashErrorMessage: [Current thread is 1 (Thread 0x7f8abf4f88c0 (LWP 22866))]
[New LWP 22868]
[New LWP 22869]
[New LWP 22870]
[New LWP 22871]
[New LWP 22872]
[New LWP 22873]
[New LWP 22874]
[New LWP 22925]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007f8ac372faff in __GI___poll (fds=fds@entry=0x7ffce48d9028, nfds=nfds@entry=1, timeout=timeout@entry=1000) at ../sysdeps/unix/sysv/linux/poll.c:29

Thread 9 (Thread 0x7f8a9a3a8700 (LWP 22925)):
#0  0x00007f8ac3c0a0d0 in QMutex::lock (this=this@entry=0x55bf330f36c0) at /usr/include/c++/9/bits/atomic_base.h:769
#1  0x00007f8ac3e49eb2 in QMutexLocker::QMutexLocker (m=0x55bf330f36c0, this=<synthetic pointer>) at ../../include/QtCore/../../src/corelib/thread/qmutex.h:233
#2  QThreadData::canWaitLocked (this=0x55bf330f3690) at ../../include/QtCore/5.15.2/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:272
#3  postEventSourcePrepare (s=0x7f8a9008b7d0, timeout=timeout@entry=0x7f8a9a3a7af4) at kernel/qeventdispatcher_glib.cpp:260
#4  0x00007f8ac19bc72f in g_main_context_prepare (context=context@entry=0x7f8a902d2570, priority=priority@entry=0x7f8a9a3a7b80) at ../../../glib/gmain.c:3619
#5  0x00007f8ac19bd0db in g_main_context_iterate (context=context@entry=0x7f8a902d2570, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4027
#6  0x00007f8ac19bd2e3 in g_main_context_iteration (context=0x7f8a902d2570, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#7  0x00007f8ac3e49fbb in QEventDispatcherGlib::processEvents (this=0x7f8a90161f40, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#8  0x00007f8ac3dee1ab in QEventLoop::exec (this=this@entry=0x7f8a9a3a7cc0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#9  0x00007f8ac3c08a12 in QThread::exec (this=this@entry=0x55bf34c7eec0) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#10 0x00007f8ac2efdfa9 in QQmlThreadPrivate::run (this=0x55bf34c7eec0) at qml/ftw/qqmlthread.cpp:155
#11 0x00007f8ac3c09bac in QThreadPrivate::start (arg=0x55bf34c7eec0) at thread/qthread_unix.cpp:329
#12 0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f8aa64ea700 (LWP 22874)):
#0  __GI___libc_read (nbytes=16, buf=0x7f8aa64e9ab0, fd=12) at ../sysdeps/unix/sysv/linux/read.c:26
#1  __GI___libc_read (fd=12, buf=buf@entry=0x7f8aa64e9ab0, nbytes=nbytes@entry=16) at ../sysdeps/unix/sysv/linux/read.c:24
#2  0x00007f8ac1a0589f in read (__nbytes=16, __buf=0x7f8aa64e9ab0, __fd=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/unistd.h:44
#3  g_wakeup_acknowledge (wakeup=0x7f8a9c0039a0) at ../../../glib/gwakeup.c:210
#4  0x00007f8ac19bccfe in g_main_context_check (context=context@entry=0x7f8a94000c20, max_priority=2147483647, fds=fds@entry=0x7f8a94004a60, n_fds=n_fds@entry=1) at ../../../glib/gmain.c:3825
#5  0x00007f8ac19bd152 in g_main_context_iterate (context=context@entry=0x7f8a94000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4044
#6  0x00007f8ac19bd2e3 in g_main_context_iteration (context=0x7f8a94000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#7  0x00007f8ac3e49fbb in QEventDispatcherGlib::processEvents (this=0x7f8a94000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#8  0x00007f8ac3dee1ab in QEventLoop::exec (this=this@entry=0x7f8aa64e9cc0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#9  0x00007f8ac3c08a12 in QThread::exec (this=this@entry=0x55bf24a98d50) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#10 0x00007f8ac2efdfa9 in QQmlThreadPrivate::run (this=0x55bf24a98d50) at qml/ftw/qqmlthread.cpp:155
#11 0x00007f8ac3c09bac in QThreadPrivate::start (arg=0x55bf24a98d50) at thread/qthread_unix.cpp:329
#12 0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f8ab5c6c700 (LWP 22873)):
#0  0x00007f8ac372faff in __GI___poll (fds=0x7f8a9c004e60, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f8ac19bd1ae in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7f8a9c004e60, timeout=<optimized out>, context=0x7f8a9c000c20) at ../../../glib/gmain.c:4346
#2  g_main_context_iterate (context=context@entry=0x7f8a9c000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4042
#3  0x00007f8ac19bd2e3 in g_main_context_iteration (context=0x7f8a9c000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#4  0x00007f8ac3e49fbb in QEventDispatcherGlib::processEvents (this=0x7f8a9c000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#5  0x00007f8ac3dee1ab in QEventLoop::exec (this=this@entry=0x7f8ab5c6bcc0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#6  0x00007f8ac3c08a12 in QThread::exec (this=this@entry=0x55bf247f8a30) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#7  0x00007f8ac2efdfa9 in QQmlThreadPrivate::run (this=0x55bf247f8a30) at qml/ftw/qqmlthread.cpp:155
#8  0x00007f8ac3c09bac in QThreadPrivate::start (arg=0x55bf247f8a30) at thread/qthread_unix.cpp:329
#9  0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f8ab67fc700 (LWP 22872)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55bf2444bac8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55bf2444ba78, cond=0x55bf2444baa0) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55bf2444baa0, mutex=0x55bf2444ba78) at pthread_cond_wait.c:638
#3  0x00007f8abc7ade6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f8abc7ada6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f8ab6ffd700 (LWP 22871)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55bf2444bacc) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55bf2444ba78, cond=0x55bf2444baa0) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55bf2444baa0, mutex=0x55bf2444ba78) at pthread_cond_wait.c:638
#3  0x00007f8abc7ade6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f8abc7ada6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f8ab77fe700 (LWP 22870)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55bf2444bac8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55bf2444ba78, cond=0x55bf2444baa0) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55bf2444baa0, mutex=0x55bf2444ba78) at pthread_cond_wait.c:638
#3  0x00007f8abc7ade6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f8abc7ada6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f8ab7fff700 (LWP 22869)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55bf2444bac8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55bf2444ba78, cond=0x55bf2444baa0) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55bf2444baa0, mutex=0x55bf2444ba78) at pthread_cond_wait.c:638
#3  0x00007f8abc7ade6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f8abc7ada6b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f8abe601700 (LWP 22868)):
#0  0x00007f8ac19b972f in g_source_unref_internal (source=0x7f8ab8004fe0, context=0x7f8ab8000c20, have_lock=1) at ../../../glib/gmain.c:2184
#1  0x00007f8ac19bb185 in g_source_iter_next (iter=iter@entry=0x7f8abe600af0, source=source@entry=0x7f8abe600ae8) at ../../../glib/gmain.c:1049
#2  0x00007f8ac19bc66b in g_main_context_prepare (context=context@entry=0x7f8ab8000c20, priority=priority@entry=0x7f8abe600b70) at ../../../glib/gmain.c:3597
#3  0x00007f8ac19bd0db in g_main_context_iterate (context=context@entry=0x7f8ab8000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4027
#4  0x00007f8ac19bd2e3 in g_main_context_iteration (context=0x7f8ab8000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#5  0x00007f8ac3e49fbb in QEventDispatcherGlib::processEvents (this=0x7f8ab8000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#6  0x00007f8ac3dee1ab in QEventLoop::exec (this=this@entry=0x7f8abe600cb0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#7  0x00007f8ac3c08a12 in QThread::exec (this=this@entry=0x7f8ac2b9dd80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#8  0x00007f8ac2b19f4b in QDBusConnectionManager::run (this=0x7f8ac2b9dd80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:179
#9  0x00007f8ac3c09bac in QThreadPrivate::start (arg=0x7f8ac2b9dd80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:329
#10 0x00007f8ac22cd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#11 0x00007f8ac373c293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f8abf4f88c0 (LWP 22866)):
[KCrash Handler]
#6  0x00007f8ac189d794 in QWaylandClientExtensionPrivate::handleRegistryGlobal (data=0x55bf302421e0, registry=0x55bf24248ad0, id=54, interface=..., version=1) at global/qwaylandclientextension.cpp:67
#7  0x00007f8ac1879822 in QtWaylandClient::QWaylandDisplay::registry_global (this=<optimized out>, id=54, interface=..., version=1) at qwaylanddisplay.cpp:396
#8  0x00007f8ac18a7d16 in QtWayland::wl_registry::handle_global (data=0x55bf24246df0, object=<optimized out>, name=54, interface=0x55bf304155b0 "org_kde_kwin_blur_manager", version=1) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qarraydata.h:236
#9  0x00007f8abf8c5ff5 in ffi_call_unix64 () at ../src/x86/unix64.S:101
#10 0x00007f8abf8c540a in ffi_call_int (cif=<optimized out>, fn=<optimized out>, rvalue=<optimized out>, avalue=<optimized out>, closure=<optimized out>) at ../src/x86/ffi64.c:669
#11 0x00007f8ac17f53a8 in wl_closure_invoke (closure=0x55bf304154d0, flags=1, target=<optimized out>, opcode=0, data=<optimized out>) at ../src/connection.c:1018
#12 0x00007f8ac17f1c48 in dispatch_event (display=display@entry=0x55bf2424ac00, queue=<optimized out>) at ../src/wayland-client.c:1445
#13 0x00007f8ac17f321c in dispatch_queue (queue=0x55bf2424acd0, display=0x55bf2424ac00) at ../src/wayland-client.c:1591
#14 wl_display_dispatch_queue_pending (display=0x55bf2424ac00, queue=0x55bf2424acd0) at ../src/wayland-client.c:1833
#15 0x00007f8ac17f3280 in wl_display_dispatch_pending (display=<optimized out>) at ../src/wayland-client.c:1896
#16 0x00007f8ac1879155 in QtWaylandClient::QWaylandDisplay::flushRequests (this=0x55bf24246de0) at qwaylanddisplay.cpp:221
#17 0x00007f8ac3e266f0 in doActivate<false> (sender=0x55bf24275060, signal_index=3, argv=0x7ffce48d9e20) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:395
#18 0x00007f8ac3e1fa87 in QMetaObject::activate (sender=sender@entry=0x55bf24275060, m=m@entry=0x7f8ac4089b60 <QSocketNotifier::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffce48d9e20) at kernel/qobject.cpp:3946
#19 0x00007f8ac3e2a733 in QSocketNotifier::activated (this=this@entry=0x55bf24275060, _t1=..., _t2=<optimized out>, _t3=...) at .moc/moc_qsocketnotifier.cpp:178
#20 0x00007f8ac3e2aed3 in QSocketNotifier::event (this=0x55bf24275060, e=0x7ffce48da0f0) at kernel/qsocketnotifier.cpp:302
#21 0x00007f8ac49eddc3 in QApplicationPrivate::notify_helper (this=this@entry=0x55bf24243a10, receiver=receiver@entry=0x55bf24275060, e=e@entry=0x7ffce48da0f0) at kernel/qapplication.cpp:3632
#22 0x00007f8ac49f6bb8 in QApplication::notify (this=0x7ffce48da420, receiver=0x55bf24275060, e=0x7ffce48da0f0) at kernel/qapplication.cpp:3156
#23 0x00007f8ac3def69a in QCoreApplication::notifyInternal2 (receiver=0x55bf24275060, event=0x7ffce48da0f0) at ../../include/QtCore/5.15.2/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:325
#24 0x00007f8ac3e4aba5 in socketNotifierSourceDispatch (source=0x55bf24261500) at kernel/qeventdispatcher_glib.cpp:107
#25 0x00007f8ac19bcfbd in g_main_dispatch (context=0x55bf24274cc0) at ../../../glib/gmain.c:3309
#26 g_main_context_dispatch (context=context@entry=0x55bf24274cc0) at ../../../glib/gmain.c:3974
#27 0x00007f8ac19bd240 in g_main_context_iterate (context=context@entry=0x55bf24274cc0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4047
#28 0x00007f8ac19bd2e3 in g_main_context_iteration (context=0x55bf24274cc0, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#29 0x00007f8ac3e49fa2 in QEventDispatcherGlib::processEvents (this=0x55bf242617c0, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#30 0x00007f8ac3dee1ab in QEventLoop::exec (this=this@entry=0x7ffce48da300, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#31 0x00007f8ac3df6354 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#32 0x000055bf23f55372 in main (argc=<optimized out>, argv=<optimized out>) at ./app/main.cpp:221
[Inferior 1 (process 22866) detached]