Fira Github por Usuário 13703371 do Firefox

The extension looks through a specific set of elements on github's pages to find areas where code will be displayed.

It then makes three small modifications on the code:
— the line height is increased to 1.5em
—text size is made 16px
—last the font family is made Fira Mono

Some people find this typographical combination lends itself to an easier reading experience.