Helps narrow and tall items stand while you try to take pictures of them. The curved piece gets glued down to the slot and the stands are supposed to be swappable. 

The base in the photos is of an earlier version with a smaller chamfer. The uploaded 3mf model has a larger chamfer which I think looks nicer & also helps hide the seam that was introduced by the density changes in the print.

If you want to print a custom stand, the dimensions are:

and the tab is 10 mm in length.

Recommended print settings:

• 10% infill or higher
• base printed upside down, with support
  • If you are feeling optimistic about your printer's part-cooling capabilities, the bridge is going to be 50 mm in length w/o support. If you do this, make sure the printhead is moving back and forth not side to side, after slicing the model.
• stands printed right side up
• two ways to print the curved plate:
  1. Laying flat on the bed may result in 'steps' on the top surface due to the wide arc, which will look ugly. However, this method provides additional grip that helps prevent the displayed item from sliding off. 
  2. Alternatively, printing on its side can provide a nice finish, but it is recommended to use a wide brim as the contact area will be relatively small.