I would like to know who this AirTag belongs to

Hello there,

Im not sure how much information beyond a serial number you'll actually get, unless it's been placed in Lost Mode, but you can try;

1. 1. Tap and hold the the top of your iphone to the white side of the Airtag
   2. You should get a notification on your screen, tap it and it should take you to a website that will provide you information about the AirTag.
   3. If the owner has marked it as lost you should see contact information or a message the owner has added if they have placed the AirTag in lost mode.

I do not know of a way Apple provides for doing that. Note that Apple is pretty good about ensuring privacy for everybody.