Re: override/delete translation of C-S-y?

[Phil Sainty]

I'll add that "(emacs)Modifier Keys" says:

   A <Control>-modified alphabetical character is always considered
case-insensitive: Emacs always treats ‘C-A’ as ‘C-a’, ‘C-B’ as ‘C-b’,
and so forth.  The reason for this is historical.