Man pages matching name event::rpc::message::json in section 3pm:

Event::RPC::Message::JSON.3pm.en	debian 10 / libevent-rpc-perl
Event::RPC::Message::JSON.3pm.en	debian 11 / libevent-rpc-perl
Event::RPC::Message::JSON.3pm.en	debian 12 / libevent-rpc-perl