Simple enough, this is a length of skirting board for a 1:12 dolls house. The Fusion 360 file is included with parameters so you can change any of the various measurements. Obviously you can change just it's length more easily with the fabulous Prusa Slicer.
Sorry for the confusing photo, but if you view the full picture you can just see the skirting board behind the ottoman and beside the wardrobe. That is the deal for skirting boards after all - nearly always concealed behind other things, ah well.
The author marked this model as their own original creation.