Actually, I must amend what I said: I was talking about Fira Mono rather than Fira Code. Fira Code fixes the r glyph (its default r glyph is excellent and its alternative perfectly respectable, still having narrowed the base line), and offers a better ampersand as an alternative. Dunno about the f ligations (ff, fi, &c.), hopefully they ditched that madness (even if they’re opt-in discretionary ligatures in Fira Mono—they just have absolutely no place in a monospaced font, dlig or no dlig).

It seems like I might have to make another amendment as I just came across something labelled Fira Mono that also seems to have the fixed r glyph. I’m throwing in the towel, there are too many things called Fira Mono and Fira Code and I can’t find any one sound canonical source; some seem to say there are a bunch of changes between the two, others seem to say it’s only a different line-height; did they perhaps start out more different but get mostly merged back? I give up. All I know is that places like bugzilla.mozilla.org and crates.io use bad versions of some Fira monospace font.