In Short: If you've been looking to get the Pixel Launcher with Google Assistant on the search bar, well, you're in luck, as you can now sideload it. This Pixel Launcher was taken from the Android Studio emulator it seems, and it will come pre-installed on the Google Pixel 3 and Pixel 3 XL handsets. This port was discovered by paphonb, a member of the Lawnchair Launcher team, and the developer of the Rootless Pixel 2 Launcher. It is worth noting that you can sideload this launcher on your device, but only if your device is running Android Oreo or Android Pie, but keep in mind that you won't be able to do it on the Pixel 2 or the Pixel 2 XL as the launcher packages will conflict. We've also tried to install it on the Xiaomi Mi 5 (which is running Oreo), and succeeded, but couldn't get it to work, as it kept on crashing.
Background: We've seen reports of a Pixel Launcher with a Google Assistant shortcut in the search bar earlier, and it was expected to arrive to the Pixel 3 and Pixel 3 XL. Not long ago, the Pixel 3 and Pixel 3 XL renders surfaced, showing off that very search bar on the home screen, and now you can get that functionality on your device without a problem. Google's Pixel Launcher has been available for quite some time now, and Google keeps on adding to its functionality. A while back, the company has decided to move the search bar right above the navigation bar, so that the search bar is easily accessible even if you're holding your device with one hand.
Impact: If you don't use Google Assistant, installing this APK doesn't make much sense, as that is the only notable change that you will see in the launcher, no new functionality has been added, at least it seems like that at first. Google's Pixel Launcher is not one of the most customizable launchers out there, or anything of the sort, but it's clean and functional, and that's why quite a few people are sticking with it.