Google API Oauth - refresh tokens?

[Ben Rubinstein]

Back in 2018 when I was originally working with Google sheets, the OAuth 
authorisation once granted seemed to refresh automatically.

That is, if a call returned the 'unauthorised' error, calling OAuth with the 
same parameters would briefly display a sheet dialog, but it would go away 
automatically.

Then I finished working on that project, and when six months I briefly looked 
at this again, fell victim to bug #22557.

Now that this is fixed, I'm happily working with the system again (and will 
shortly release my code in case it's of use to anyone) - but now when the 
authorisation expires (which is does after an hour or so), calling Oauth2 goes 
through the process requiring user activity.

There's an OAuth2Refresh command in LiveCode; but the issue is that I don't 
get a refresh token from the Google API. From my reading of the docs, only 
certain kinds of app registered with Google get refresh tokens - but I don't 
seem to be able to figure this out.

Has anyone managed to register an app with Google (in 
https://console.developers.google.com/apis/) in a way that means it gets 
refresh tokens?