There is a mess with Fira Mono for this release. Please see:
https://github.com/ryanoasis/nerd-fonts/issues/1003
The FiraMono zip still got Fura Mono * ttf files.
Homebrew choosed to still name the package Fira but adapted to contains the Fura files.
https://github.com/Homebrew/homebrew-cask-fonts/pull/6682
Anyway it looks like Fira will last for Mono and Code.