Oculus + Unity + Chromatic abberations

Where I can get the direct access to the shader?
I want to get full control of creating image: correct some values, etc.
I can't find.
Is it in the DLL?
Thanks!

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added:
I don't completely understand what happens when I click "Attach to Unity" in the place where usually "Start Debug" button.

I want to understand how it works.

Call stack does not help me because functions are called from the outside process. I need to see whole program, if it is allowed.