Konsole doesn't honour the KDE accessibility setting 'flash window' - unlike all other terminals I've tried: xterm, Eterm, rxvt, gnome-terminal, IntelliJ's terminal panel.
STEPS TO REPRODUCE
1. Settings> System Settings> Personalisation> Accessibility> Use visual bell> Invert screen (actually, window).
2. Open a new Konsole
3. Press 'backspace' to cause a beep.
Nothing at all. Not even a beep.
It would trigger accessibility's beep logic and invert the window or whatever else is configured.
Linux/KDE Plasma: Ubuntu Ubuntu 18.04.3 LTS with kubuntu-desktop installed on top.
KDE Plasma Version: kde-plasma-desktop/bionic 5:100ubuntu2 amd64
KDE Frameworks Version: plasma-framework/bionic,now 5.44.0-0ubuntu3 amd64
Qt Version: qt4-default/bionic 4:4.8.7+dfsg-7ubuntu1 amd64 (qtchooser -print-env says 4)
It clearly knows about the beep - I can add a notification to get it to announce one - but even with the notorious issues surrounding getting sound to work on Linux, it should honour the visual accessibilty setting at least as well as a non-KDE app.
I know I can add a command to trigger when the bell rings, but the point is that accessibility settings should just work. (xcalib -i is massive overkill)
*** This bug has been marked as a duplicate of bug 407821 ***
noticed it on Fedora 31 too