Please consider to use a new name for variable font

[stone-zeng]

Now the static fonts and the variable version share the same name Fira Code, however, it will lead to some issues when both are installed. For example, macOS's font book will complain duplication, and TeX/dvipdfmx will fail to compile if in the look up ordering the variable version may be prior to the static ones (see #1156).

So please consider to use another name, such as Fira Code VF to resolve these problems. The same way has been adopted by Source Code Pro (Source Code Variable). Thank you!

[tonsky]

Good point, thank you!