Q: What is System Preferences.app

If you go to System Preferences -> iCloud -> iCloud Drive Options there is "System Preferences.app" at the bottom of the list.

What is that?

Namely, when I disabled it, I got 1.6 GB more space in my iCloud, which gives me the impression that it stores a huge amount of "something" in the iCloud. Now I enabled it again but I can't see any change in the storage consumption, which then means that it didn't put that "something" back to the iCloud when I enabled it again.

So, in my iCloud storage bookkeeping, I lost 1.6 BG of data but I have no idea what data that was because it was never visible, for example, in the iCloud Drive.