I see - once again, instead of just letting people fund the damn browser, Mozilla is continuing with its tried-and-true strategy of randomly integrating things into other things.
It has been confirmed that none of the donated money (Mozilla Foundation) goes to Firefox development (Mozilla Corporation). You hear the comment often because it is true.
There's no option to donate to a specific project, though. As much as I'd like to support Firefox, I do not want to support any other shiny projects that they'll kiff of in a year or two.