Bug 479427

SUMMARY
As we know, Konsole doesn't copy text with ^C because that would interfere with both shell interrupt, as well as any apps using CUA bindings for copy in many in-terminal apps as well as ^C is fairly special for Emacs as well... So that's great
...
BUT....
One of the key combos that konsole absorbs by default is C-x,R,M for add bookmark, and C-x, R, L for edit bookmark.

So not only is C-x also a CUA key shortcut for CUT that many in-terminal apps will hope to get, it's also a very very special key  for Emacs.

Now, that might not actually be too catastrophic, if after you press the 2nd key, say C-x f, and it realises, ok, "f" means nothing to me after C-x, that konsole released BOTH keys to the in-terminal app... so that at least eventually the app gets to see the whole sequence of C-x f, but it seems to me that if you press C-x, konsole will completely absorb it, on the possibility that you may next press R, and if you don't press R, then tough, the C-x goes to nowhere, and the next character goes to the terminal.

Now it seems to me, that to not be anti-social, all the standard keybindings should have at least 2 modifier keys to try and not conflict with any in-terminal app.... and someone should check with some of the most famous and common apps as  well, which surely Emacs qualifes as.

Another set of keys that clearly conflict with Emacs are the Alt+1, Alt+2, Alt+3 etc bindings which are used by Emacs.

I'm also skeptical of konsole absorbing an unmodified F11 to maximise, when KDE has its own maximise key- Win-PGUP. Surely if someone wanted to take the time to learn a key combination for full screen, they'd learn the one that works in all apps, not just konsole.

STEPS TO REPRODUCE
1.  Open a konsole with standard keybindings
2. start emacs
3.  Try and exit emacs with C-x C-c

OBSERVED RESULT

Doesn't exit because konsole absorbed the C-x

EXPECTED RESULT

1. If konsole sees a key that is the beginning of a key sequence, send ALL the keys to the app once it becomes apparent that it wasn't in fact the beginning of a known key sequence.

2. Reconsider some of the default keys for being anti-social to in-konsole apps.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma:  Arch Linux current
KDE Plasma Version: 5.27.10
KDE Frameworks Version:  5.113.0
Qt Version:  5.15.11

ADDITIONAL INFORMATION