I can't find any information about whether or not the Amazon Fire TV (original release as of the posting of this question) supports the HbbTV specification.
I'm building an app using the TAL framework, and I've successfully added my hello world application as a web app hosted on my local server to the Amazon Fire TV, via the Web App Tester Tool.
But I am at a loss with HbbTV. Perhaps Amazon doesn't support it? I can't find any documentation that says either way.