Fira Code extends Mozilla’s monospaced Fira Mono with ligatures for common programming sequences. The reasoning is that, for a reader of code, the eye spends effort joining several characters into one meaning. It treats combinations such as -> or <= as a single logical token and draws them as one symbol. This is only a rendering feature: the underlying code stays plain ASCII.
The ZIP has four static styles: Regular, Medium, SemiBold and Bold. The original variable font runs from Light to Bold, so the thinnest weight is left out and this pack uses static files. There are no italics, which matters little in code, where emphasis is rare. Characters are included for Latin, Central and Eastern European Latin, Cyrillic and Greek.
Use it in code editors, terminals, documentation and technical blog posts. Ligatures only appear where the app supports them, and some people dislike them, in which case another monospace is a better choice. Compare it with Hack or Cascadia Code, and set surrounding prose in Inter.