Oracle engineers suppose to open new bugs in its internal bug database until they think opening them in public one makes sense.
Example of such a case is Bug #68415 "resolveip and mysqlaccess still use gethostbyaddr"
Reason for making it public is that it describes behavior, which was introduced into the tools resolveip and mysqlaccess without intention and they now still can work with NetBIOS name, different or not existent in DNS while MySQL server cannot.
Interesting fact that such NetBIOS names were not ever officially supported, but they worked until deprecated function gethostbyaddr was replaced with recommended to use getnameinfo. And since NetBIOS never was claimed to be supported there is nothing to document in the officail user manual! While this hardly affects many people, because new Windows API does not support NetBIOS anyway, having such a bug public can help those who use antique versions of Windows and NetBIOS names.