Function region_at_floored 

pub fn region_at_floored(
    local: Point,
    size: Size,
    set: DropRegionSet,
    factor: f32,
    floor: f32,
) -> Option<DropRegion>

region_at with band_depth’s floor applied per axis.

Priority is core’s, unchanged: leading → trailing → top → bottom → centre, so an overlapping pair still resolves the way the un-floored function does and a caller that reads the region index reads the same thing.