To keep track of cut and fill quantities, important volumes, or stockpiles you can use the Saved Quantities tool in the sidebar.
For example, you calculate the cut/fill balance for a specific area and want to save the boundary for the future reference. After selecting the area, click Save and enter the name of calculations.
To edit the calculation area select the edit button, drag points to modify the area, and save. The graph and tracking will recalculate to the new area defined.
To turn on the calculations, select Saved Quantities in the sidebar, select the folder and click on the name.
This image features an old UI. Updated version coming soon!