@parker >current owners of the code
I can't believe I missed this massive error at first.

Copyright is held and not owned, otherwise copyright would never expire, just like how a house you own doesn't fall into the public domain after a set number of years.

Most of winamp appears to be free software that actually implements everything, although there is code that implements a GUI (in Qt) and some proprietary libraries.

The original authors could have sold the copyright of their code to another party, but the sale of a copy of the current code in its current state was not legal, as it appears there is a mix of incompatible licenses and a lot of deleted copyright headers.