6. How does Waterfox make money?

Waterfox has search partnerships. That is, the default search on Waterfox is monetised. If you search with it, Waterfox gets a share of the revenue. You are under no obligation to use the default search - but if you like what Waterfox does and want to support the project, please consider using it.

Source: https://www.waterfox.net/docs/faq/