So lets say you have a team that handles user on-boarding and account management. If you want a top bar with the user name, does this feature have to be owned by the user account team? If they're different teams with different microfrontends, how does the top bar frontend know to update based on activity in the account management frontend?

Basically, cross vertical information will exist, how do you solve the caching problems? Maybe some kind of app wide message passing?