Sony's latest phone, the Xperia XZ Premium, launched in the United States last week. As the name implies, it's a rather expensive phone ($799.99), but offers a few unique features like a camera capable of recording 960FPS slow-motion video. Sony has now added the phone to its Open Devices program, making it easy for developers to build AOSP for the device.
If you're unfamiliar with the Open Devices program, Sony periodically releases device-specific binaries and build instructions for its new phones, allowing developers to easily create their own custom ROMs. The XZ Premium's device configuration is now live on GitHub, and Sony even provides a guide for compiling AOSP Nougat 7.1.
Developers can find more information at the source link below. Sony notes that building Android 7.1 is currently "experimental," and could result in a slightly-unstable ROM.