What's the difference between `/private/var/db/receiptss/` and `/var/db/receipts/`?
The files are not duplicates, but, linked.

At the top level of the hard drive, /var is linked to /private/var; and, /tmp to /private/tmp

So, /var/anydirectory would also show up as /private/var/anydirectory.  Deleting one will also delete the other.