[Idea] You could use fontvs.com to check what your font supports.

I stumbled upon this site recently, so I uploaded the Nerd Font TTC and found some information and the compatible languages of the font:

these styles and OTF features

I think it would be really useful to see what characters, glyphs, ligatures, features, and whatever else is missing. Now there is also FontForge, but using this in combination with FontForge just might be useful.