Fira is based on FF Meta, by Spiekermann. Trebuchet is an imitation of FF Meta. https://blog.tilton.co/2013-08-01-fira-feura-typeface-from-mozilla.html https:

Fira is based on FF Meta, by Spiekermann. Trebuchet is an imitation of FF Meta. https://blog.tilton.co/2013-08-01-fira-feura-typeface-from-mozilla.html https://blog.tilton.co/2013-08-01-fira-feura-typeface-from-m...