I don't understand the point of this at all. The idea of the Mozilla Foundation was to be a non-profit to promote web standards. So it makes a lot of sense to work on their own rendering engine Gecko, which can be used to implement new web standards, and a browser that contains it (Firefox).
This is just a WebKit shell. What purpose does it serve that furthers that goal? Is Mozilla abandoning Gecko in favor of WebKit? They've said several times that would never happen because multiple implementations (engines) are needed to have a real standard, yet they are now promoting Apple's WebKit version.
Calling this a browser is a lie. Mozilla went from being a company that made browsers and made it a statement to point out where this was not allowed (Apple's ecosystem, and recently Microsofts) to a company that is comfortable locking itself in into those closed ecosystems with fake products that do nothing to promote the open web, perhaps even on the contrary.
That said, I can't seem to find anything on Mozilla's pages, so for all I know this is the press getting things entirely wrong yet again. But I'd love to see some clarification here - it's almost unbelievable if this goes through.