Histogram values of viewer node

Hi guys,

I’m new to color correction and reading histograms. I hope someone can explain what is exactly going on in the images below.
First image shows the histogram of the original black n white gradient, with values I expect.
Second image shows the same gradient but via the compositor viewer node and now the values go all weird. What is happening here?

My goal is to bring balance in my renders by color correction and trying to understand things like this as good as possible.

if you can help, many thanks!

Solved it by setting the View Transform to Default in Color Management tab. This was set to Filmic.