Error with matlab.apputil.install

Hello all,

I am interested in a app from File Exchange, I downloaded it and I had a surprise seeing an .mlappinstall file. I documented about it, but I am confused about this "matlab.apputil.install". Matlab is saying:* "Undefined variable "matlab" or class "matlab.apputil.install"."*

Is this an extra tool or how can I make it work? Thank you!