Wow. Do you happen to know if that just for API-based usage, or for downloads too?
> The Google Fonts API currently does not support requesting the inclusion of optional (also known as discretionary, or opt-in) OpenType Features, such as Stylistic Sets (salt) or Small Caps (smcp, c2sc). Instead the glyphs contained in these features may be published as a separate family…https://googlefonts.github.io/gf-guide/requirements.html#ope...
Sometimes they might also ship outdated versions, e.g. the last released version of Fira Sans is 4.301, but Google still only serves version 4.203. Plus technically Fira Sans has been superseded by Fira Go, which includes additional scripts, but Google doesn't offer that one at all.
> The Google Fonts API currently does not support requesting the inclusion of optional (also known as discretionary, or opt-in) OpenType Features, such as Stylistic Sets (salt) or Small Caps (smcp, c2sc). Instead the glyphs contained in these features may be published as a separate family… https://googlefonts.github.io/gf-guide/requirements.html#ope...