I understand that there is a rule on Top Tabs that they must have at least one viewport with no base object set and that viewport to be the default. This is because, when you first enter an Interface you will have not interacted with the user to select a data object / record.
There is, however, one exception. The default user on the User object is always known.
Can you therefore please allow a Top Tab to have its default viewport to have a base object if that base object is ‘User’ and set equal to Default User.
This will be very useful so that, from the outset I can use the Viewport header and nuggets to display information relating to the user (e.g. the team or company they belong to).