| Subject: | Concrete license |
https://metacpan.org/pod/CPAN::Meta::Spec#license allows being concrete. Open-Source isn't a valid license - it just says "trust me, it's approved" - shouldn't be used when better options are available.
Suitable seems to be
license => [ qw(perl_5 bsd) ] (in case you mean 3-clause BSD, and not 4-clause (unusual meanwhile) or 2-clause).
Thanks,
Jens