Motorola published its first kernel based on Android 5.1 earlier this month. That was for the 1st generation Moto G LTE. Now it has published the bits for the 2014 Moto X, codenamed Victara.
The files are available over on Moto's GitHub page. There isn't much reason for general users to download them, but developers can use the code to produce custom ROMs or test out apps.
You can get the goods at the link below.