What is "picom" doing here?

I use the current and updated NomadBSD and I looked at the running processes because the fan in my laptop is working more than usual. This is a screenshot of HTop.

There are 2 processes from picom, using around 39 % of my CPU. After a few minutes it got better, but picom now needs around 30 % of the CPU.
I use NomadBSD with ZFS and Nvidia graphics. I only know that picom is a compositor for Xorg. But I don’t know what it is exactly doing in NomadBSD.
I use several other systems on the same laptop, Win 11, Puppylinux and Fedora 38. None of these systems uses so much CPU power while being idle. I would like to understand why picom uses so many resources.