I was more wondering about the drill.txt file being empty, but now it looks like fab houses will have a problem.
When you export it this is all you get.
; NON-PLATED HOLES START AT T1
; THROUGH (PLATED) HOLES START AT T100
I was wondering if there was a special way to draw it.
It's a 1mm slot 2mm long.
The main problem is that the pins are 1.5 x 0.8mm, so a round hole would be huge.
I can't remember seeing a part in FZ with a slot.