https://addons.mozilla.org/en-US/firefox/addon/audrey-hepburn2003/ - original
https://addons.mozilla.org/en-US/firefox/addon/motyw-koci-171/ - duplicate
I hadn't thought to check for a duplicate initially because it wasn't showing as a Probable Duplicate Submission. It wasn't until the designer uploaded another design that I knew right away was a duplicate that I decided to check the first design they uploaded. And sure enough, it was a duplicate as well.