How does one distinguish between Android and IOS Firebase IDs for Push Notifications?

Information about an app instance is available from the Instance ID Service at this endpoint:

https://iid.googleapis.com/iid/info/IID_TOKEN

On success the call returns HTTP status 200 and a JSON object containing various status for the app instance including the platform:

returns ANDROID, IOS, or CHROME to indicate the device platform to which the token belongs