Missing translations in pt (Portuguese)

I found many missing translations in language code pt (Portuguese). Most of them are not missing in pt_BR. I would like them to be translated from English or at least copy the pt_BR version. For example I’m using FileExtensionValidator, and the default message is in English and not translated to Portuguese. I don’t speak Portuguese myself and therefore I don’t want to join the Portuguese team. But I would like the pt language to be complete.