Kopia also means a copy in Polish and the author is Polish. The first paragraph in the software's Github page also confirms the Polish origin of the name: https://github.com/kopia/kopia/
Tangentially, as far as OSS names of Polish go, kopia is pretty tame. A popular deduplicating app is named czkawka (hiccup). Now that choice is just mean towards non-Polish speakers. :)