"Lightroom CC" does not exist anymore, it's an old name. If you 'migrated'. then you probably migrated from Lightroom Classic to Lightroom (destkop). Before anyone can advise you to trash photos, we have to be sure that's what you did, so please specify.
You are correct. Sorry for the confusion. I too was confused and was basing it on file folders. Lightroom classic created a file folder called Lightroom and the current Lightroom created a Lightroom CC folder where all my migrated photos are. it did migrate successfully and create copies. I had to do this very carefully as I did not want to lose any photos.