Recent-ish Firefox Android builds use Open Sans. https://blog.mozilla.org/ux/2013/03/improved-type-on-firefox-for-android/ https://blog.mozilla.org/ux/2013/03/

Recent-ish Firefox Android builds use Open Sans. https://blog.mozilla.org/ux/2013/03/improved-type-on-firefox-for-android/ https://blog.mozilla.org/ux/2013/03/improved-type-on-firefox...