That is an LED or RBG display pattern.
Depending on how the original was made, it is either the result of photographing the image right on the screen or a simulation thereof.
Basically it is a dot pattern. In a "real" display the RGB are separated into their own slots. If you look at your monitor screen with a magnifying lens you can see this for yourself.
A simplified approach is to use an overlay of such a pattern.
Kinda like this, but softer: https://www.filterforge.com/filters/10412.html