We just got the message about migrating from shinyapps.io to Connect Cloud. Some of our apps use Shinyapps authentication on shinyapps.io to identify the user, which is simple: we just look at session$user in the server function, which is the user's email address that they use to log in to shinyapps.io.
Posit Connect Cloud uses a different method. The docs at Visitor Information – Posit Connect Cloud Documentation say "The header is a standard JWT whose sub claim is a unique identifier of the Connect Cloud user making the request."
I'd like to understand the format of this unique identifier. Is it the user's email address or login id? If not, how can we use it to identify the user?