Random New Folder After Manual Upgrade - Safe to Delete?

So I just performed a manual upgrade to 17.0. Everything is working great, I just have one question. I have a new folder that was created alongside my external data directory. The new folder is named “nextcloud” and just contains a bunch of random files like “oc_addressbookchanges.ibd”. I renamed the folder and restarted Apache and Nextcloud seems to still work just fine, so I’m guessing it’s just some temporary files left over from the manual upgrade, but I want to make sure before I actually delete these files.

Note this folder is not within my data directory, it is alongside it. For example, my data directory is /mnt/storage/Nextcloud , this new folder in question is /mnt/storage/nextcloud (lowercase n, so a separate folder since Linux is case sensitive).

Edit: I had previously attempted to perform a normal upgrade using the grpahical tool within Nextcloud, and the upgrade basically froze and never completed, hence my resorting to doing it manually. Could these files be left over from that interrupted/failed upgrade?