On opening some sites, e.g. https://www.eqtpartners.com/About-EQT/ I've got an "SSL Certificate Error!" window with message that certificate isn't trustworthy. But there is no any information about the reason, why it is treated in such way. Especially while both Chromium and Firefox open this site without question. The reason would be quite useful for making decision for allowing certificate. This is slightly related to https://bugs.kde.org/show_bug.cgi?id=387210 but has different user case.
*** This bug has been marked as a duplicate of bug 387210 ***