2014-2018 Mazda 3 Skyactiv Appearance & Interior
On my 2017 Mazda3 hatchback, I've discovered a second button, and I don't know what it is for. I've just looked through the owner's manual, and I found nothing about it.
If you lift the hatch and look up where the camera and open button is, from left to right is:
backup camera | hatch open...