Duden mentions this: "Bei Verwendung von Großbuchstaben steht traditionellerweise SS für ß. In manchen Schriften gibt es aber auch einen entsprechenden Großbuchstaben; seine Verwendung ist fakultativ ‹§ 25 E3›."
But isn't it also dependent on the available glyphs in the font used? So f.e. it needs to be ensured that U+1E9E exists?
I don't think there exists any code that makes uppercasing decisions based on the selected font. Besides, if it doesn't exist in the current font, there's probably a fallback font.
But isn't it also dependent on the available glyphs in the font used? So f.e. it needs to be ensured that U+1E9E exists?