This would be specifically useful for project reports. I'm constantly running project reports for various months, years, etc and by the time the report is created I forget the period I ran the report for. This would also be helpful on balance sheets and income statements although, I know sometimes your data includes multiple years so maybe you could identify which date to include in your header (i.e. which column date range to match in the header).
Hello! We do have this feature for the Income and balance reports on the headings tab. We do not have it for our other reports but I think it's a great idea!