The hairy blur is a cat showing his disdain for this sort of litter box.
You can see the "urine flask" at the front. It has a nice gasket closing the flask (seriously, what the heck is it called?), and a lid. The lid seems very important.
The holes at the front separate the urine. Other functions may be carried out with the trapdoor open or closed. The main idea is to keep the two separate; apparently the mixing of urine and feces is the reason an outhouse smells like an outhouse, and a holding tank smells like an outhouse. I can't say! Later, I can say!
It opens like this:
Here is the solar vent shed:
I want to use it, right now. Excuse me.