Note that there's separate work going to revitalize the Wikipedia app for
Firefox OS, which will remain HTML5-based as that's how native Firefox apps work!
I was going to ask if this could be a Wikipedia app for Firefox in general, since most of Mozilla's WebAPIs are available on Firefox for Android and desktop Firefox[1]. But the current version already is!, https://marketplace.firefox.com/app/wikipedia installs on desktop Firefox.
Since all the second-tier phone OS are saying "write HTML apps for us", with some app manifest munging might the Firefox app work on them too? At what point does a Web app become a modern HTML5 web site, or is it vice versa? :)