Man pages matching name parallel::forkmanager in section 3pm:

Parallel::ForkManager.3pm.en	debian 10 / libparallel-forkmanager-perl
Parallel::ForkManager.3pm.en	debian 11 / libparallel-forkmanager-perl
Parallel::ForkManager.3pm.en	debian 12 / libparallel-forkmanager-perl