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

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