Man pages matching name filesys::diskspace in section 3pm:

Filesys::DiskSpace.3pm.en	debian 10 / libfilesys-diskspace-perl
Filesys::DiskSpace.3pm.en	debian 11 / libfilesys-diskspace-perl
Filesys::DiskSpace.3pm.en	debian 12 / libfilesys-diskspace-perl