Whether to request confirmation before visiting a new file or buffer.
The variable `confirm-nonexistent-file-or-buffer' determines the
return value, which may be passed as the REQUIRE-MATCH arg to
`read-buffer' or `find-file-read-args'.
Whether confirmation is requested before visiting a new file or buffer.
If nil, confirmation is not requested.
If the value is `after-completion', confirmation is only
requested if the user called `minibuffer-complete' right before
Any other non-nil value means to request confirmation.
This affects commands like `switch-to-buffer' and `find-file'.