HDB::Object uses Class::HPLOO but not listed in Users tab

[hakonhagland]

See

https://cpants.cpanauthors.org/release/GMPASSOS/Class-HPLOO-0.23/used_by

and

https://metacpan.org/release/HDB/source/lib/HDB/Object.pm#L35

[charsbar]

It is because your HDB distribution's META.yml says it only requires DBI.
https://metacpan.org/source/GMPASSOS/HDB-1.05/META.yml#L8

Generally speaking, CPAN toolchain including CPANTS trusts META files more than what's declared in each .pm file, because the latter may be a conditional requirement (consider Win32 module in ::Win32 namespace in some distributions, which is not supposed to be used by other OS users, and thus, can't be declared as a solid requirement in META files). In this case Class::HPLOO is considered such a conditional module, and thus, is ignored.