/usr/share/applications/ubuntu-amazon-default.desktop is in unity-webapps-common 2.4.17+15.10.20150616-0ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | [Desktop Entry]
Name=Amazon
Type=Application
Icon=amazon-store
Exec=unity-webapps-runner --amazon --app-id=ubuntu-amazon-default
|