Comment by bonzini

There's Mozilla Foundation (where making a browser is not on the road map) and Mozilla Corporation (which makes money by making a browser to finance the foundation).

Mozilla Corporation revenue is about half a billion, most of it coming from Google and only 2% (from what I found) going to the foundation. The foundation gets most of its money from Google as well, but separately, and the foundation's revenue is about 10% of Mozilla Corporation's. So overall over 90% of Mozilla's budget goes to software development and to cost centers that are associated to Mozilla Corporation.