I got a segmentation fault, downgrade solved the problem. Here is a backtrace

Thread 1 "keepassxc" received signal SIGSEGV, Segmentation fault. QList<QString>::detach_helper (this=0x7fffffffca48, alloc=<optimized out>) at /usr/include/QtCore/qlist.h:718 warning: Source file is more recent than executable. 718 if (!x->ref.deref()) (gdb) bt

0 0x00007ffff70525fa in QList<QString>::detach_helper(int) (this=0x7fffffffca48, alloc=<optimized out>) at /usr/include/QtCore/qlist.h:718

1 0x00007fffe5b19c2e in QList<QString>::reserve(int) (alloc=1, this=0x7fffffffca48) at /usr/include/qt5/QtCore/qrefcount.h:102

2 0x00007fffe5b19c2e in QList<QString>::QList(std::initializer_list<QString>) (args=..., this=0x7fffffffca48)

at /usr/include/qt5/QtCore/qlist.h:165

3 0x00007fffe5b19c2e in QStringList::QStringList(std::initializer_list<QString>) (args=..., this=0x7fffffffca48)

at /usr/include/qt5/QtCore/qstringlist.h:110

4 0x00007fffe5b19c2e in GnomeHintsSettings::kvantumThemeForGtkTheme() const (this=<optimized out>) at ../src/gnomehintssettings.cpp:455

5 0x00007fffe5b1d799 in GnomeHintsSettings::loadTheme() (this=0x555555a5d6e0) at ../src/gnomehintssettings.cpp:282

6 0x00007fffe5b1de8c in GnomeHintsSettings::GnomeHintsSettings() (this=0x555555a5d6e0) at ../src/gnomehintssettings.cpp:109

7 0x00007fffe5b18ba2 in QGnomePlatformTheme::loadSettings() (this=0x555555a0d2f0) at ../src/qgnomeplatformtheme.cpp:127

8 0x00007fffe5b18be8 in QGnomePlatformTheme::QGnomePlatformTheme() (this=0x555555a0d2f0) at ../src/qgnomeplatformtheme.cpp:33

9 0x00007fffe5b188fc in QGnomePlatformThemePlugin::create(QString const&, QStringList const&) (this=<optimized out>, key=..., paramList=...)

at ../src/platformplugin.cpp:27

10 0x00007ffff72852b6 in QPlatformThemeFactory::create(QString const&, QString const&) (key=..., platformPluginPath=...)

at kernel/qplatformthemefactory.cpp:51

11 0x00007ffff728e068 in init_platform

(argv=<optimized out>, argc=@0x7fffffffd17c: 1, platformThemeName=..., platformPluginPath=..., pluginNamesWithArguments=...)
at kernel/qguiapplication.cpp:1228

12 0x00007ffff728e068 in QGuiApplicationPrivate::createPlatformIntegration() (this=0x5555559a8100) at kernel/qguiapplication.cpp:1373

13 0x00007ffff728f375 in QGuiApplicationPrivate::createEventDispatcher() (this=<optimized out>) at kernel/qguiapplication.cpp:1390

14 0x00007ffff6d0cd35 in QCoreApplicationPrivate::init() (this=this@entry=0x5555559a8100) at kernel/qcoreapplication.cpp:844

15 0x00007ffff7290af3 in QGuiApplicationPrivate::init() (this=this@entry=0x5555559a8100) at kernel/qguiapplication.cpp:1419

16 0x00007ffff77ebded in QApplicationPrivate::init() (this=0x5555559a8100) at kernel/qapplication.cpp:564

17 0x00005555555c9c69 in Application::Application(int&, char**) (this=0x7fffffffd1e0, argc=<optimized out>, argv=<optimized out>)

at /usr/src/debug/keepassxc-2.4.3-5.fc29.x86_64/src/gui/Application.cpp:50

18 0x00005555555b4272 in main(int, char**) (argc=<optimized out>, argv=0x7fffffffd428)

at /usr/src/debug/keepassxc-2.4.3-5.fc29.x86_64/src/main.cpp:62

The same issue with NET::ERR_CERTIFICATE_TRANSPARENCY_REQUIRED as in f30. Downgrade to 75.0.3770.100-3.fc29 solves the problems.

https://bodhi.fedoraproject.org/updates/FEDORA-2019-5d2420030c