I was talking in context of variable fonts which come with lots of features mapped to opentype tags and axes. font-feature-settings property selects (or activates) those features. Usually this is done at few CSS selector levels. The variable fonts can be trimmed by freezing those features. I did something like this with Fira Code a few years ago. [1]
> I would like to do the subset font optimization. I'm just not sure how much of an improvement it's going to be. Have you done it manually before?
It can be quite an improvement for fonts like Inter which ship with massive number of glyphs to support different languages.[2] Doing this manually is a huge pain. Zach Leatherman created a tool called Glyphhanger to automate some of the usecases [3]
[1]: https://github.com/naiyerasif/FiraSourceMono
[2]: https://paulcalvano.com/2024-02-16-identifying-font-subsetti...
