Pixel 2’s portrait mode has been ported to non-Google devices running Oreo

[cdmagurus.com]

Android developers have modified the Google Camera .APK to support Portrait Mode on non-Google Oreo devices. Here's where you can download the new app to try it out on your phone.

More... (https://phandroid.com/2018/01/02/pixel-2-portrait-mode-apk/)