How to delete a new apple loop from the loop library

Hello,

This is what happened: I dragged a downloaded apple loop into the loop browser in Logic Pro X. Then I couldn't delete it from the library. I have tried many ways to locate the loop on my MacBook Pro. It is not in the folder "Apple Loops" in the library (as showed in some answers to similar questions before), and I have searched for it on the whole Mac but got no result.

Now the loop is still there and playable in Logic. I guess it may be stored in a hidden folder but have no idea where it is. This is not a big deal, but it is a mystery to me. I would appreciate it if anyone knows why. Thank you!