> Also, if someone wanted to "shed" the identity associated with a public key they could always just "accidentally" leak the private key in a public git commit.

That would allow anyone to prove that they owned the public key, which prevents the original owner from using it. But it seems like, if you want to stop using the key, it's simpler to just stop using it. What does leaking the private key accomplish that deleting the private key doesn't also accomplish?