You can see the latest revision of the proposal here:
https://tymi.org/P3673R0

Motivation: In C++, most string-oriented functions have wide-character
string representations (such as std::format and friends,
std::cout/std::wcout, all C string APIs etc), but std::print/std::println
seem to be missing wide-character string support. I understand this feature
might not appeal to people who don't use wide-character strings, but these
are quite common in the language, and I find a need for wide-character
formatted output to be standardised.

Tymi.