Function rs::data::loading::iter_layout_sources

fn iter_layout_sources(
    name: &str, 
    arrangement: ArrangementKind, 
    purpose: ContentPurpose, 
    ui_overlay: Option<&str>, 
    layout_storage: Option<PathBuf>
) -> impl Iterator<Item = (ArrangementKind, DataSource)>

Returns possible sources, with first as the most preferred one. Trying order: native lang of the right kind, native base, fallback lang of the right kind, fallback base