Something special about Ctrl+Shift+C?

[rrr@xxxxxxxx (Rene von Rentzell)]

I just stumbled into a weird XY-4 problem. Is this a bug, or
a "feature", or should I RTFM?

What happened was that I accidentally pressed Ctrl+Shift+C. XY4
promptly exited XY4, and then crashed the computer when i tried
to reload.
The file I was working with was, naturally, gone. I lost about 1
hour of work, unpleasant enough, but I can live with it if I know
this doesn't happen again.

I looked at the keyboard file I am using; taken from XY-3 and modified
a little bit. There is no entry for 46= in the Ctrl+Shift section, so
for all that I can imagine, the key combination should do nothing.

What is going on? Can somebody explain? TIA

-- Rene 
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