似乎Web商店希望将_locales目录添加到带有子文件夹(在我的情况下为"en_US")的根目录中，并附带正确设置的messages.json文件.遵循对应用进行本地化指南中的信息，即可解决此问题.

It seems the Web Store wanted a _locales directory added to the root with subfolders ("en_US" for my case) and accompanied by properly setup messages.json files. Following the information from the Localizing your app guide resolved the issue.

希望Google可以将其错误消息更改为找不到_locales目录"，而不是我们当前收到的清单错误.

Hoping Google can change their error message be something like "_locales directory not found" rather than the manifest error we currently receive.