Bug 472799

SUMMARY
Konqueror does not offer configuration of certificates in its own settings. Konqueror in view mode WebEngine silently ignores trusted certificate settings from KDE Settings -> Network Settings. There is now way to add trusted CA certificates nor client certificates.


STEPS TO REPRODUCE
1. Open KDE System Settings -> Network -> Settings -> SSL Settings
2. Beneath the list of system installed trusted CA certificates, click "Add..." and add another CA certificate
3. Open Konqueror and open an https URL pointing to a server signed by the CA just added

OBSERVED RESULT
Konqueror will show the site as untrusted


EXPECTED RESULT
Konqueror will successfully validate the site as signed by a trusted CA.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5:142
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
It is not even possible to add a user certificate in the system settings dialogue, in result it is oviously impossible to configure client certificates.
I did not test if deactivating a system-wide CA certificate in the KDE settings dialogue would result in Konqueror not trusting that CA anymore, as expected. It seems rather improbably as Konqeror appears to just ignore the system settings.
It remains absolutely unclear, which certificates _are_ trusted by Konqueror.