SE-0278: Package Manager Localized Resources

Linking related discussion about this: Package Manager Localized Resources - #22 by SDGGiesbrecht

TLDR the behavior is defined, and can be changed, by the top-level Application. It can choose whether to use it's own default, or mix the defaults.

Then if the Package doesn't support either, my understanding is when a localized-resource is accessed without the needed localization, it would default to that Bundle's defaultLocalization.