They mean like you walk up to a public stall, you see it’s empty (because it’s see through glass), so you know it’s safe to go in. You lock the door when you go in and it turns opaque so nobody can see you pooping.
Edit: I found a video of what they are talking about. Apparently it’s also so that you know the bathroom is clean and not gross so you aren’t discouraged from using it. Pretty neat. https://youtu.be/KGoKsv2omBU?si=F0ig6oFHtavzZY9z
They mean like you walk up to a public stall, you see it’s empty (because it’s see through glass), so you know it’s safe to go in. You lock the door when you go in and it turns opaque so nobody can see you pooping.
Edit: I found a video of what they are talking about. Apparently it’s also so that you know the bathroom is clean and not gross so you aren’t discouraged from using it. Pretty neat. https://youtu.be/KGoKsv2omBU?si=F0ig6oFHtavzZY9z
Ah, I see now, I thought this was a group of stalls in a larger toilet, not separate toilets. It does seem pretty neat.