I want to use the Fira Code font in RStudio 1.2.5033. I installed the font on my system (Linux 5.5.13-arch2-1 x86_64). I checked that it is available (e.g. in LibreOffice). Interestingly, I could also see it by means of the extrafont R package through plotting within RStudio. But, invariably, it fails to show under Tools > Global Options > Appearance. I only have 6 font options there, no matter how many TTF monospace fonts my system has installed. Any advice on how to proceed is very appreciated. Thanks in advance.