Man pages matching name moose::meta::typeconstraint::union in section 3pm:

Moose::Meta::TypeConstraint::Union.3pm.en	debian 10 / libmoose-perl
Moose::Meta::TypeConstraint::Union.3pm.en	debian 11 / libmoose-perl
Moose::Meta::TypeConstraint::Union.3pm.en	debian 12 / libmoose-perl