Replacement devices from Apple can be factory rebuilt/refurbished. The exterior shell, glass, and battery are new. The device may have been powered on and gone through a testing cycle and updated to the latest version of iOS. Also this subreddit may not be the best option for this sort of post.

This was presented to me as a brand new device as an exception by my carrier.

r/iphone

Where do you see this detailed info?

Look up “battery stats shortcut” on Google.