Well, often there will be a radius, up to 0.35mm or whatever else the toolhead can reach, enough to give a sharp appearance.
For some sections there may well be toolheads that can produce a straight transition.
Also instead of zero draft you can use 0.25 degrees which up to three inches will look virtually straight.
Unlike what textbooks say, a lot more is possible with injection molding nowadays.
It is a combination of smart tooling and part design strategies. You may design a partial draft on the inside so while the part is in cooling phase it shrinks onto the core but also away from it in mold release direction.
Gas/air assisted ejection is another option.
As for the LEDs, many plastics are by themselves somewhat translucent. White PS is a good example but also PP will work.
You can design specific lighting modules inside but even if you place an LED behind a thin matte translucent acrylic part so it catches and diffuses the light you can see it as a defined shape on the outside.