print-escape-nonascii

print-escape-nonascii is a variable defined in `C source code'.
Its value is

nil

Documentation:
Non-nil means print unibyte non-ASCII chars in strings as \OOO.
(OOO is the octal representation of the character code.)
Only single-byte characters are affected, and only in `prin1'.
When the output goes in a multibyte buffer, this feature is
enabled regardless of the value of the variable.