Constant UI_SANS_FAMILY 

pub const UI_SANS_FAMILY: &'static str;

Product-wide primary font families. Tilo ships these exact faces, and the renderer also assigns them to the CSS-like generic families below. Keeping the names here makes plain text, rich text, and theme tokens agree instead of depending on each machine’s fontconfig defaults.

The UI face covers Latin, Vietnamese and Greek. Cyrillic falls back to a face matched to it, sized to its x-height (see crate::font_catalog); every other script falls back to Noto.