val mtime_of_source_object: source_object -> float option
val mtime_of_target_object: target_object -> float option
val is_readonly_buri_of: options -> source_object -> bool
val mtime_of_source_object: source_object -> float option
val mtime_of_target_object: target_object -> float option
val is_readonly_buri_of: options -> source_object -> bool