We were amused to see the note left by some previous owner, or maybe the builder.
Glen began by cutting into the space to see what was there.
First, he drilled a guide hole from the inside and left the bit in temporarily
so he could see where the hole in the brick should go.
Then the lengthy process of drilling a 6" hole through the brick wall.
Glen bought a special blade to go on his drill for this task.
Part-way through.
Yay! There's a hole in the wall.
Now the hole is occupied by the exterior vent.
The installation is still visible (until Glen patches the drywall).
It works! Steam from the fryer is being sucked up instead of setting off the alarm.