What happens after the Nest access token expires?

nest-api, rest

Solution

Expiration date comes back in the OAuth response and is set to 10 years in the future, which is practically forever. That gives Nest quite a few years to come up with a refresh or expiration story.

Problem

Question says it all. I couldn't find anywhere in the API that states what happens when it expires. Do you have to open that "Works with Nest" webpage again and get a new authorization code? Or, using the same authorization code, just get a new token? And how will Nest indicate the token has expired?

Original source