Check that link: http://www.ghacks.net/2016/01/09/mozilla-to-remove-webrt-from-firefox/
The news is very sad for me, i have a talk about that http://mte90.github.io/Talk-FF-OWA and with the remove of that feature we cannot fight the chrome apps and other implementations.
The marketplace have the roles as a marketplace only for Firefox OS.
While for the http://www.w3.org/2008/webapps/manifest/ W3C Manifest there are no news for Firefox support.