Apple has been using Helvetica as the system fonts for iOS since the first iPhone, and they also switched the fonts from Lucida Grande to Helvetica for Mac OS X since 10.10 Yosemite. Why did Apple decide to ditch Helvetica, which is the most famous and loved font in the world?

Fira Code is an extension of the Fira Mono font containing a set of ligatures for common programming multi-character combinations. 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. https://github.com/tonsky/FiraCode#browser-support