There are source3/locale/pam_winbind/*.po, but they are not build, neither by default, nor manually by waf. I updated them at https://gitlab.com/samba-team/samba/-/merge_requests/1574 At least ru.po was in quite good shape!
This bug was referenced in samba master: e8f31e5c23434ca04c921693376624a44dc36849