Man pages matching name log::handler::output::sendmail in section 3pm:

Log::Handler::Output::Sendmail.3pm.en	debian 10 / liblog-handler-perl
Log::Handler::Output::Sendmail.3pm.en	debian 11 / liblog-handler-perl
Log::Handler::Output::Sendmail.3pm.en	debian 12 / liblog-handler-perl