Debugging output of GUI apps

I have been hit by #643726 again. I was happily working on a terminal while an apt upgrade was running on another, and suddenly kbuildsycoca4 started vomiting on my command line because I had run okular once on that terminal last tuesday.

Among the possible workarounds, one can run kdebugdialog from package kde-runtime and check the "Disable all debug output" button.

This is the output of kdebugdialog when run on a terminal after enabling "Disable all debug output":

$ kdebugdialog
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.
QDBusConnection: session D-Bus connection created before QCoreApplication. Application may misbehave.

I see it as debugging output turned into an art performance, and I have an appreciation for this kind of things. kdebugdialog, my hat's off to you.