Daeken, I thought the only thing users could download to their B2G phones were web applications. There is zero support for native apps, like alternative browsers, right?
Yeah, I'm struggling to see how a browser could possibly be implemented in another browser and expect to have competitive performance. Especially when Gecko will be running native code, and any other browser would not be.
Native apps on Boot2Gecko are web applications, by definition. And you're free to implement alternative browsers on top of that -- even if you're still using Gecko underlying everything, you can give a vastly different experience. Arguing that they can't run their own engine code is a technical issue, not a business/political issue.
Also, one of the key things about Boot2Gecko is that it's intended to be reimplemented. You could make a Boot2IE phone or Boot2Chromium phone; you swap out the low level but keep everything on top of it the same. Everything is built on real web standards that are free to be implemented by all. It's truly open, top to bottom and bottom to top.
I think the original question was more like: can a third party like Opera or Microsoft port their browser to B2G and make it available through the B2G store. As an app.
The answer is no because third party B2G apps cannot be written in C or C++.