The Absolute Light is a verse that contains all possible types of light, as well as an infinite number of all possible light spectrums (and many other spectrums), each represented with a single Absolute Colors. It is one of, and may just be, the brightest verse period.
Many barriers are too weak to withstand the forces of all the light particles hitting them. One of the only barriers that can contain it is The Absolute Dark, and even then, some light still escapes. Other barriers, like the Lockverse, are much too small to be used as a barrier, so it is unknown if they could withstand the forces.
The Absolute Light only contains Absolute Colors, and due to the laws of this verse, stretch each of their spectrums out (you can see a small number of them in the image) into a sort of 'tail' where light is emitted. This is why The Absolute Light is so bright.