On OS X/MacOS, the GalaxyClient has a privileged helper process called com.gog.galaxy.ClientService, located in /Library/PrivilegedHelperTools/com.gog.galaxy.ClientService that is a Mach-O 64-bit executable, started as a Launch Agent.

It runs as root.

I do not like the fact that it runs as root, as this might cause security issues in the future, and has the fun ability to potentially wreak havoc on my computer.

What does it do? How well audited is it? I presume it's doing some sort of UI/process overlay thingy, but I don't know. Should I be worried about the fact that it's a ~2 MiB daemon that I can't control?

interesting question i too must have this answered

I'm not noticing it with Activity Monitor with Galaxy either open or closed.

In Galaxy, have you selected the option to have it started with the computer? It's called "Start GOG Galaxy Client with OS". I'd guess that would have something to do with it.

I agree, admin use is always presented as ominous, so it's always more comfortable not having extra admin processes. I would think GOG would be interested in not opening themselves up (both application and their reputation) to being taken advantage of by outside manipulation of their software (hijacked admin processes), if even only from their own programming errors. Unless they think they are perfect at programming and the imperfections of other hardware and software won't affect their own perfection?