Function diff_driver_forces_text 

pub fn diff_driver_forces_text(
    git_dir: &Path,
    config: &ConfigSet,
    path: &str,
) -> bool

True when a path’s diff=<driver> attribute pairs with an explicit diff.<driver>.binary=false.

Git resolves the driver before the big-file shortcut and keeps such paths textual even above core.bigFileThreshold.