Square hole in the back of air intake box
So I was checking my air filter on my 08 civic lx coupe today and I noticed in the back of the box for the filter there was a square hole on the back of it that went out underneath the tube for the intake going to the motor from the box. I felt in the there because I couldn't really see into it very good and it felt like it curved to the right. I'm not sure what this hole is, it doesn't look like its for the EGR but there's too much stuff in the way to get a clear view of what's behind the air box. I'm just curious as to what it could be for because I've never noticed it before today.