It’s a Test Function option which pops up in SAMSUNG phones where you can enjoy different colors of light right from ypur Samsung mobile. You can test your sensors, cameras, sound and touch calibration also.
I became aware of this from my friend . It’s a useful option where you don’t need to download any apps for your Samsung phone.
You don’t need to have a Smartphone to do this you can do this with any of your Samsung phone.
I haven’t tried it on other phones
Do try and let us know in the comments section below…….