Man pages matching name net::idn::uts46::_mapping in section 3pm:

Net::IDN::UTS46::_Mapping.3pm.en	debian 10 / libnet-idn-encode-perl
Net::IDN::UTS46::_Mapping.3pm.en	debian 11 / libnet-idn-encode-perl
Net::IDN::UTS46::_Mapping.3pm.en	debian 12 / libnet-idn-encode-perl