Empty AssetsV2 folder in Finder
Danger Will Robinson! 

Not sure why it matters that you have an empty folder in /System/Library but I have found from past experience that you NEVER touch anything in the /System folder. Doing so can lead to problems with your Mac up to and including making it non-bootable.

I completely ignore all folders outside of my home folder. Sure it is interesting to go exploring but honestly if it ain't broke don't fix it. And an empty folder takes up so little space on disk it's not worth deleting.