Top-left, around 7cm (3in) from the corner, or ~2.5cm (1in) down the side: Thin ZIF interface cable for the whole keyboard/backlight/tablet.

Top, between 4.5 and 70cm (~2 and 3 inches) from the left corner: the flexible cable folds over here and is very close to the edge.

Left side, 1.5-4cm (~0.5-1.5 in) down from top: there's a folded layer of (I think) digitizer here. I didn't run into it, but careful to not cut too deep.

Left side, 12-15cm down from the top: there's a spot of copper foil protecting some delicate folded traces below.

Bottom, from left all the way to center: The wifi antennas are here. They are basically conductive paper, stuck onto a piece of plastic, with the screen adhesive stuck on top of that. I completely destroyed the first ones, and still damaged 1 of 3 on the second. Recommend not cutting here at all if possible.

Except for these two haptic vibration motors, you should not need to cut more than 4mm deep on the sides, and maybe 8mm deep on the top/bottom.