Actually none of that stuff in the thread or linked does a good job if you don't know what it is at all.

LS replaces explorer as the desktop shell. The taskbar and desktop icons are replaced. That's all explorer, and any LS theme with them is doing emulation (though pretty good as of late). Beyond that, what it is depends a lot on the theme. Modules loaded add functionality, and that can be basically anything, though there is a finite amount of modules available.