HDRP Change post processing behavior through script (C#)

How do I change the post processing in HDRP through script?

For example Post Exposure value of the Color Adjustments component of a UnityEngine.Rendering.Volume?

I can't assign the UnityEngine.Rendering.Volume variable of my script in the Editor.
Is there a way to get the currently active, global Volume?
Is there a better way to get a local Volume besides checking against the collider and then accessing the Volume via GetComponent?

 

Is there any documentation on this? I can't find a thing.

 

If the HDRP PP scripting side continues to works like PP v2, then this should provide some help:
https://answers.unity.com/questions/1355103/modifying-the-new-post-processing-stack-through-co.html
https://github.com/Unity-Technologies/PostProcessing/wiki

HDRP related questions are probably better suited for the graphics sub-forum:
https://forum.unity.com/forums/graphics-experimental-previews.110/