There are a lot of ways information about new phones and phone software can leak, which is why they're so prevalent. What isn't as common is a company accidentally leaking its own stuff, but it happens. Case in point, Google seems to have accidentally revealed that Android P will have gesture controls similar to those found on the iPhone X. But obviously better because it's being done by Google and not Apple.
Over on the Android Developer's Blog, Google announced that the Android P Developer's Preview would be prioritising DNS over TLP, which is a technical network security improvement that nobody cares about unless they're a developer or a huge nerd (possibly both). But the original blog post came with a little extra, in the form of a screenshot that seemingly displayed a brand new type of navigation menu. What's more, that screenshot has since been removed and replaced with something new that crops out the navigation menu. So clearly there's something to hide.
According to 9to5Google, there have been murmurs that the company is testing a brand new navigation bar and the brief presence of that screenshot seems to confirm it. What's more the site's sources claim that the company will be using a pill-shaped button (see below) for gesture control - specifically to replace the multitaking button with a single upward swipe gesture.
As you can see above that button has vanished, though thankfully Google hasn't removed the back button. That said, 9to5Google claims the back button will only automatically hide when it's not being used, which suggests you might have to perform some sort of on-screen gestures for it to appear - much like you do to pull up the virtual navigation bar.
So far this feature is only in the testing phase, and it wouldn't be the first time Google tested something that was pulled before the full stable release. No doubt we'll be hearing more about this sort of thing when Google reveals what Android P will be able to do at I/O next month. [9to5Google via The Verge]