"Kerberos" without any qualifiers can mean the protocol (version 5 or version 4) or an implementation (often the MIT implementation). "MIT Kerberos" can mean the cross-platform krb5 source code product, or the rebranded Leash GUI that's part of KfW. "Kerberos 5" usually means version 5 of the Kerberos protocol, but "MIT Kerberos 5" usually means the krb5 source code product. Sometimes people write "Kerberos 1.13" when they mean "krb5-1.13", and sometimes they write "MIT Kerberos 4.0" when they mean kfw-4.0. This can get very confusing. We should figure out a better way to brand things.