Man pages matching name io::async::os::cygwin in section 3pm:

IO::Async::OS::cygwin.3pm.en	debian 10 / libio-async-perl
IO::Async::OS::cygwin.3pm.en	debian 11 / libio-async-perl
IO::Async::OS::cygwin.3pm.en	debian 12 / libio-async-perl