Man pages matching name locale::recodedata::koi8_u in section 3pm:

Locale::RecodeData::KOI8_U.3pm.en	debian 10 / libintl-perl
Locale::RecodeData::KOI8_U.3pm.en	debian 11 / libintl-perl
Locale::RecodeData::KOI8_U.3pm.en	debian 12 / libintl-perl