Starting from Power BI Сonnector version 1.4.1 new Show Table(s) Schema Map option was added on the data source page. This option is available only for the ServiceNow Admins role, who has a full set of permissions.
Diagram will help to select fields, especially Reference type fields, more accurately and check tables and permissions for them before the export process.
The option is allowed to see the relationship between chosen tables in Data Source, including referenced and referencing tables and all fields types:
