Man pages matching name fcgi::async::psgi in section 3pm:

FCGI::Async::PSGI.3pm.en	debian 10 / libfcgi-async-perl
FCGI::Async::PSGI.3pm.en	debian 11 / libfcgi-async-perl
FCGI::Async::PSGI.3pm.en	debian 12 / libfcgi-async-perl