Man pages matching name authen::passphrase::phpass in section 3pm:

Authen::Passphrase::PHPass.3pm.en	debian 10 / libauthen-passphrase-perl
Authen::Passphrase::PHPass.3pm.en	debian 11 / libauthen-passphrase-perl
Authen::Passphrase::PHPass.3pm.en	debian 12 / libauthen-passphrase-perl