Motorola just released the kernel source for the Moto X Pure and it is codenamed Clark. Motorola managed to push the open source code to Github where everyone can take it from and dabble in baking and tinkering with their device. This comes after the release of Android 5.1 source for the Moto X 2014.
As always, this is mostly news for developers and not the everyday user, but you may just as well benefit from it in one way or another. The kernel source is always an important step when it comes to creating good mods and apps. The source code is based on Android 5.1 and it is 145MB in size. You can go to the source link and grab it for yourself.