echo -n "5KZns" | openssl dgst -sha256
b2a950ff612a89d7fd2effa6d75acced098d9d141a559029629080c092aedf14
Yep. That's what I came up with. You can't get a sane private key out of it.
I think this is right, I don't know why it doesn't give the correct key though.
I was just going to post the exact same findings, except that at my end, I got the same key and it does convert to a public key.
It doesn't, it's not valid base58.