In the following screenshot documentation is using a small value for minimumFetchIntervalMillis without specifying that.

I have expected the value to be the default production value, or to at least have a comment that this value is a development specific value.
Reading the following text will make you even more sure that the value that was used was a production value

During development, it's recommended to set a relatively low minimum fetch interval. See Throttling for more information.

Anyway this is not related, but i also think that the throttle error can be more descriptive

firebase-remote-config.js:1 Uncaught (in promise) FirebaseError: Remote Config: The config fetch request timed out while in an exponential backoff state. Configure timeout using "fetchTimeoutMillis" SDK setting. Unix timestamp in milliseconds when fetch request throttling ends: 1585237413512. (remoteconfig/fetch-throttle).

In order to know what happened here i had to go back to documentation/source code.