Assets license?

What is the license under the assets included with the engine demos and samples? CC-0? CC-BY? Proprietary?

The assets was made by a indie game studio called N-IX, @xen2 could ask you better about the terms of the license.

"Can I use assests and code from the Xenko samples or templates in my application?

Yes, you can use Xenko sample assets and code in your games."