Thank you.  There are 2 "use". It seems not good also.

raises E_DEPRECATE. Use empty value to use default_charset setting and/or
use input_encoding, output_encoding, internal_encoding.
↓
raises E_DEPRECATED. "default_charset" is used as the default. Set empty values for "input_encoding", "output_encoding", "internal_encoding" to use "default_charset" setting.

Is this good enough? Improvements/corrections are appreciated.