Man pages matching name email::sender::transport::devnull in section 3pm:

Email::Sender::Transport::DevNull.3pm.en	debian 10 / libemail-sender-perl
Email::Sender::Transport::DevNull.3pm.en	debian 11 / libemail-sender-perl
Email::Sender::Transport::DevNull.3pm.en	debian 12 / libemail-sender-perl