From https://developer.mozilla.org/en-US/docs/Web/CSS/font-family https://developer.mozilla.org/en-US/docs/Web/CSS/font-family : system-ui Glyphs are

From https://developer.mozilla.org/en-US/docs/Web/CSS/font-family https://developer.mozilla.org/en-US/docs/Web/CSS/font-family : system-ui Glyphs are taken from the default user interface font on a given platform. Because typographic traditions vary widely across the world, this generic is provided for typefaces that don't map cleanly into the other generics.