Function configured_font_system 

pub fn configured_font_system() -> FontSystem

Build the process’s font system: the database a host built for it when there is one, otherwise the product font catalog with the system’s fonts behind it and Tilo’s script fallback (Android copies its catalog out of the APK first). A binary run from a checkout, a screenshot and the Tilo image therefore all set text in the same faces, whether or not the machine has them installed. Only when no catalog loads does it fall back to the system’s fonts alone with the generic families pinned to the product names.