It was the first phone to feature virtual navigation buttons, which would in theory allow device makers to one day create a device with no bezel. (thenextweb.com)
What's more, there were questions raised by that photo, which shows a phone that doesn't include any physical or virtual navigation buttons. (bgr.com)
To access: swipe down from the top of the home screen > hit the settings cog icon > select Navigation Key and you'll be presented with Off - screen navigation button or Virtual navigation bar. (pocket-lint.com)