Dave Mark, writing at LoopInsight:

Do you have an iPhone 6s or newer? Try this:

  • Unlock your phone.
  • Press your thumb on the left bezel (the black framing on the left side of the front of the phone) and press.

As you press, the force touch will reveal just a bit of the stack of apps you are running. Press with a bit more force, and that view will go full screen, as if you had double pressed the home button.

Not sure when this feature first came out, but it seems little enough known that I thought this was worth a post.

This feature has been out a while, possibly with iOS 10.0. Pretty sure it’s been on my iPhone 7 since the day I bought it. Usually when I trigger the feature, it’s an accident. Dave’s idea of overriding its default functionality, or maybe disabling it in fullscreen apps, would be welcome.

UPDATE: As a DC reader pointed out, this feature’s been out for more than a year.