This has to do with regulations in certain countries where it is not permitted to have the regular taillight function to disappear while the blinker is on. The current sequential red blinker function on the US spec real Mustang does not comply with this and that is why Ford developed an export spec variation (the clear ones) without the sequential option for cars that are sold outside the US or Canada.Not sure why they didn't do both top and bottom but it is unique and Mustang-like.
Hopefully they are more reliable than the turn signals on most cars on the road. After all, those millions of cars that turn without signaling can't all be bad drivers, right?One of the best features, highly visible multi segment amber lights with animation. Many vehicles have poorly viable signal lights, too low or too small/dim.