Sony Xperia XZ1
Install Android 9.0 pie on Sony Xperia XZ1 (Resurrection Remix) – How to Guide!
Install Android 10 on Sony Xperia XZ1 (LineageOS 17.1) – How to Guide!
Finally, Android 10 Q is official and so the AOSP 10 Source code.
Upgrade Guide for Smartphones
Finally, Android 10 Q is official and so the AOSP 10 Source code.