Screen brightness adapts automatically?

Today my new laptop arrived (Medion S6445) and with this laptop, the screen brightness adjusts automatically (when I'm on a white website it gets brighter, darker on dark sites.

I have not been able to find an option in Windows 10 yet where I can disable this. Does anyone know where that works?

Do you have to do manually on the screen!

I have only FN buttons here that can make the screen brighter and darker, and one to disable the screen, that's it.

In your user manual, I can't find any indication of an automatic brightness adjustment to the ambient brightness.
That would be unusual for this price range.

It would also manifest itself differently than described by you.
The screen brightness would then increase and decrease with the ambient brightness.

I've read through the manual once, but could find nothing suitable. Here is the manual in PDF format: https://drive.google.com/...sp=sharing

What I noticed: The adjustment takes place only when the laptop is operated via the battery. As soon as I plug in the power adapter, the screen stays at the set brightness

With laptops, I have little own experience.

I think that on battery operation to increase the useful life, as an energy management takes effect.

I thought so too, but I could not find anything yet