copy-region-as-kill is an interactive compiled Lisp function in `
(copy-region-as-kill BEG END &optional REGION)
:around advice: `ses--advice-copy-region-as-kill'
Save the region as if killed, but don't kill it.
In Transient Mark mode, deactivate the mark.
If `interprogram-cut-function' is non-nil, also save the text for a window
system cut and paste.
The optional argument REGION if non-nil, indicates that we're not just copying
some text between BEG and END, but we're copying the region.
This command's old key binding has been given to `kill-ring-save'.