Swift Package localization always using English Localization

The quote on StackOverflow came from here on the forums, where the context includes a broader explanation:

You have not described how the host application is set up, so I have to infer some details, but what you describe of Xcode 12.5 sounds like the intended behaviour. It also matches my memory of how it worked before, even going back all the way to before Swift existed. Is it possible something else changed and the attribution of the difference to an Xcode update is mistaken?