Source code for the kernel on a smartphone may not seem like a big deal for most people, but for developers, it's definitely a big deal. Without the source code, it makes things a bit tougher for those that want to open up the phone by flashing some custom ROMs, kernels or even a custom recovery like TWRP. Many smartphone makers don't put the source code out there for everyone to see and use, since they do sometimes contain proprietary code and can even open up the device for security risks. However, Lenovo is one of the few that do put out the source code for developers to play around with.
Lenovo's Moto Z Droid kernel source code is now on Github for anyone to download and play around with. For most users of the Moto Z Droid, this isn't going to change anything for you. But those that are out there and are tinkerers, you'll likely see a good bit more action in the development area for this smartphone. Which includes mods, custom ROMs and so much more. A bit surprising that this is happening with the Moto Z Droid, considering Verizon likes to keep their smartphones nice and locked down. Keeping their users from rooting and ROMing their devices - as Verizon thinks that will cause users to brick their device and need a new one, causing a customer service headache.
The Moto Z was announced along with the Moto Z Force at Lenovo Tech World in June. The two devices were Verizon exclusives and launched in July. The Moto Z is actually available for pre-order now, as an unlocked smartphone and will be shipping shortly. However the Moto Z Force will remain a Verizon exclusive. It's important to note here that this source code is for the Moto Z Droid version and not the regular Moto Z. That source code should hopefully appear rather soon on Github from Lenovo. This is the first kernel source code that has been made available for the Moto Z lineup. Hopefully this is the start of things to come for the other models, like the Moto Z Force and Moto Z Play.