I mean, I know she must
as she eats like a pig, isn't fat or bloated, and is very healthy... But I have never found any of it, nor have I ever seen her go.
I find the waste from my male when I vacuum his tank, so I know what it looks like... But my female? Nothing.
I vacuum her tank and always take a look in the bucket. Broken off bits of plant and a missed pellet or two, and that is it. The tank has fine sand in the bottom, so it isn't slipping down between gravel.
It is a total mystery. Where does it go?!?