Find Duplicates Plugin

I am a newbie here, so excuse me if I am asking a stupid question.
In earlier versions of Calibre there was a great plugin that I used often - Find Duplicates.
I cannot find\install it on the latest versions (9.8 can see it but would not install). Version 9.7 cannot even see it.
Is it coming? It is so useful, I would not mind paying for it.