Amazon Prime Video was released for Android TV after Google pulled out the big guns in their battle with Amazon (removing YouTube from their new Echo Show)
Has anyone tracked down the APK? It was available before the official release on XDA, but before these latest developments Amazon had taken down the XDA thread. (upset they capitulated to that)
The Prime Video Android TV App is currently in a closed beta. You can check whether you are eligible here: https://play.google.com/apps/testing/com.amazon.amazonvideo.livingroom
Once the beta testing has been finished the compatibility flags will be set.