Fira Code is a version of Mozilla's Fira Mono font with additional
ligatures.

It is an extension of the Fira Mono font containing a set of ligatures
for common programming multi-character combinations in languages
like erlang, elixir, haskell, ocaml, clojure, scala etc where these
symbols crop up frequently. This is just a font rendering feature:
underlying code remains ASCII-compatible. This helps to read and
understand code faster. For some frequent sequences like .. or //,
ligatures allow us to correct spacing.

WWW: https://github.com/tonsky/FiraCode