But, why look back a couple of years now?
If the backup/restore was successful, and Disk Drill did not stay on your Mac, and all that remained was whatever was leftover from the Disk Drill task (recovery, correct?) - but Disk Drill was removed when the tech job was complete....
Well, sure, the cleverfiles folder has some files that belong to you. Would be related to the file recovery, of course.
Hopefully, you did not start putting your current files in that folder after the recovery was complete, (?)
SO, why are you questioning the Cleverfiles folder? Its job is done (the Disk Drill software was removed)... If you think it is important to keep (or you simply don't know), why not just copy the files in that Cleverfiles folder to an external drive, then delete the complete folder on your internal drive.
Then, if you need some random file that, for some reason, moved to that folder, you will still have it.
Hopefully, you know enough about the files that you actually use, so you can tell the difference.