Firebase 身份验证没有用于 Amazon 登录的内置提供程序.这意味着，要允许使用 Amazon 帐户登录 Firebase，您必须创建一个自定义提供程序.

Firebase Authentication has no built-in provider for Amazon sign-in. That means that, to allow signing in to Firebase with Amazon accounts, you'll have to create a custom provider.

目前不支持将自定义提供商帐户链接到现有帐户(来自内置提供商).但是，如果您查看 这个 Github 线程，就会发现一些关于如何通过使用自定义声明或其他机制来实现相同的目的.

Linking custom provider accounts into existing accounts (from built-in providers) is not currently supported. But if you look at this Github thread, there's some good info on how to accomplish the same by using custom claims or another mechanism.