When I opened Firefox today there was an advertisement banner at the bottom (picture attached) that said:
“For the holidays, we got you a little something just for using Firefox! Book your next hotel stay on Booking.com today and get a free $ 20 Amazon gift card. Happy Holidays from Firefox! (Restrictions apply.)”
Terms: While supplies last. Valid for bookings made between Dec 24-31, 2018 with a price of USD 250 or greater (excluding taxes and fees). Gift card sent via e-mail 40 days after completed stay.