Using the Help Menu in Smart Center, you can find which form you have open, and if there is data showing then which table a form / sub-form is checking.
With a form open, go to Help --> Show Form/Block.
At the bottom of the screen, it will show you the name of the form (in this case, dir, for dir.fmx) and which table it's referencing (directory).
In the Listing form's Pagers sub-tab, with data populated, we see that it's the form is listing.fmx and the table is pager_assignment.
In On-Call, the form is oncall.fmx and the table is on_call_group.
In Dormant Messaging IDs, the form is dormants.fmx and the table is dormant_messaging_id.
In Holidays and Business Hours, the form is adas_holidays.fmx and the table is adas_business_hours.