Originally created in 2012–13 for the Mozilla OS and licenced under the OFL (Open Font Licence). Designed by Ralph du Carrois and team, based on Erik Spiekermann’s FF Meta. Supports Latin (incl. Vietnamese), Greek, and Cyrillic, latter with a localized Bulgarian version designed in cooperation with Botio Nikoltchev and Vassil Kateliev. Also comes in Mono and Code styles.
FiraGO is a version with even broader language coverage, developed in 2016 for geo data provider Here, supporting Arabic, Devanagari, Georgian, Hebrew, and Thai.