Containments on plasma-org.kde.plasma.desktop-appletsrc

How does it work? I mean I have several Containments numbers like: [Containments][8] … [Containments][23] … I get that some are for the background of plasma where the wallpaper goes, some are for panels

But overtime it seems it gets messy, with repeated background ones and panels.

I guess I want to know how plasma interprets it, whats the logic for these IDs and why as I change my plasma settings the amount of containers increase even if I don’t add more panels, screens etc.