User Account Settings- Other Users- what is Secure Assessment Account?

[Windows Central Question]

I am running build 14291 of 10 and noticed this today. I have no idea if it was in any earlier builds. It seems like a pretty nice idea- restricting that account to only accessing one web page. I tried to test it out, but I cannot select an account to have 'secure assessment'.
Any one know what this is, and if it is a new feature, or something I'm missing in the setup?
I thought it could be very nice for digital signage, or registration kiosks or something.