Hole in pistons

I have a 99 metro with a 1.3l, no problems, but looked into cylinder to see a perfect 1/8" hole in the same spot on each piston. Is this a manufactured design, or problem?

If you had actual holes in the pistons, you would have no compression and the car would not run. I never seen a G13 piston, so I am not sure if those are manufactured.

The car runs fine, the holes are perfect 1/8" diamater by 1/8" deep with a bit of chamfer at the top, and in the exact same location in each piston.

There most likely notched valve reliefs then.