My brother-in-law and my niece built this in a few days to be the main bathroom of their cordwood house. The gas fired toilet was a disaster. The composting toilet did not work properly in the cold. So, this is just a very cute shed on the property. It would make a lovely retreat or spare bedroom. It is actually large enough to be a tiny house.
Notice the concrete pads as in the shed below.
No need to be too fussy with this tiny a structure.
Notice too, the brackets supporting the roof overhang on the front. These could just as well be extensions of the ridge pole and top plates, perhaps decoratively carved or chamfered.
There are no windows in the sides so that privacy could be maintained as a bath, but they could easily be framed for windows and/or a glass door for more light inside.