Relocated Items folder

I personally just look through quickly it to make sure there aren't any pictures, documents, etc. -- That would be unlikely since it's usually just full of incompatible system files -- and then delete the folder. Sometimes you'll get a message that files are in use. So at the next restart I delete the rest. I've also just deleted the alias on the desktop and left the folder. I've never had an issue with deleting files from there. It's supposed to be incompatible files so there should be no harm.

For the most part, if you migrated from a much older OS, you may have been storing files on the root level of the hard drive (i.e., open Macintosh HD and save there). That is no longer allowed, so those file would have been moved into the Relocated Items folder.

The second possibility of files you might have need of is if you configure some of the underlying server software, like SMB or Apache. If you do, the upgrade/update may have moved those configuration files into Relocated Items.

If none of that applies to you, then you can pretty much always ignore the folder.

If you didn't see anything in there that is important to you, just delete it.