Which is the license of XXX?
Fira Sans
Fira Sans (initially called Feura Sans) is a humanist sans-serif typeface designed by Erik Spiekermann, Ralph du Carrois, Anja Meiners and Botio Nikoltchev of Carrois Type Design for the Firefox OS. Fira was released in 2013 initially under the Apache License and later reissued under the SIL Open Font License.
SIL Open Font License