They currently have search deal with google. This was disclosed in their yearly financial statements. ~90% of their revenue comes from google.
https://www.computerworld.com/article/3487825/mozilla-in-tro...
Cadence's point is very valid. Mozilla gets funding by charging search engines to be the default in Firefox and that isn't changing anytime soon.
I wish people didn't instinctively downvote when someone is wrong on a technicality, but this is a site filled with nerds after all lol
EDIT: i guess he isnt even technically wrong.
I know they terminated it (and kept the money) when Yahoo was sold to Verizon but I had not heard they signed a new deal with Google, I assume they were surviving off the Yahoo Money still