This one is a quite complex one. It allow to use the Parent Input layer
You got several presets examples that show how this modifier can be used let's take the example of the "Auto-Resolution Plane setup II" inside the advanced presets.
Here you can see a Parent Input layer
layer used as mask or map of many different modifiers (in yellow). What display each one of theses layers is basically the image before being modified by the compo based modifier (on the left)
/!\ Note that there is a known bug, when using compo based presets, you'll have to first set the camera correctly inside of it (if there is as on the example above)
To do so, navigate a little bit inside the compo based, the select the camera and right click on it:
Then if your camera is correctly set it will appear like that:
This modifier allow you to create your own reusable and sharable effect.
How to do this? Here is a tutorial made by
Vincent Le Moigne