override/delete translation of C-S-y?

[Stephen Leake]

I'm trying to bind "\C-Y" to yank-from-kill-ring (I already have the
other modifies on C-y bound).

However, something is translating "\C-Y" to "\C-y"; according to the
elisp manual on translating keys, it's one of ‘input-decode-map’,
‘local-function-key-map’, or ‘key-translation-map’.

However, (lookup-key *-map "\C-Y") returns nil for all those maps, as
does (lookup-key *-map "\C-y").

I tried greping in the source to find where those keymaps are set, but I
did not find C-y.

How do I find the right key binding to override/delete?

-- 
-- Stephe