This year's flagship phone from Motorola, the Moto Z3, was something of a disappointment. Still, if you own one, here's some good news. Motorola just published kernel sources for the Z3 (codenamed 'Messi'), so developers can now easily create custom ROMs and recoveries for the phone.
Motorola is usually very punctual with kernel source releases, but this one took a while for unknown reasons — the Z3 was released in August. Better late than never, I suppose. Developers can download the source package from GitHub at the source link below.