Hi.
What value(s) are adjusted when you run deflicker? Is it exposure level only or anything else?

BR,
Lage

It's exposure on a background layer, not the "normal" exposure, which you can still keyframe independently.

Ok, so even if i have pulled the normal exposure to the max, LRT will still have headroom to adjust exposure for deflicker?
Are this background layer and its values accessible and adjustable in any way, either i LRT or LR?

BR,
Lage

Yes.
In LRT you can edit the deflicker column.