It's where you expect it to be, under the hump in front of you in the middle just behind the handlebars.
You pull the two sides outwards at the rear of the panel. There are 2 rubbery tabs that hold that in. One you pull out you then pull up and back and the while housing comes off to reveal the normal looking cover with clips all the way around.
Took me forever to find it also because you are afraid of pulling on plastic but it's meant to pop off.
My air filter was foam type just like the Uni, by the way.