Man pages matching name net::server::proto::unixdgram in section 3pm:

Net::Server::Proto::UNIXDGRAM.3pm.en	debian 10 / libnet-server-perl
Net::Server::Proto::UNIXDGRAM.3pm.en	debian 11 / libnet-server-perl
Net::Server::Proto::UNIXDGRAM.3pm.en	debian 12 / libnet-server-perl