

That’s not a valid key. OpenSSH keys are not arbitrary bytes, they contain at least the type of the certificate used and a hostname.
The fact that this is not a valid key does not mean you need to reverse engineer public keys. By design you can just get a public key with a private one.


In C# it’s certainly a label, it’s the same syntax and you can also jump to them with
goto, which is actually very convenient sometimes. As far as I know this is an ancient feature and seeing how early C# was mostly inspired by C, I would expect it to behave the same way there.