They released the source code to WinAmp and then did a WHOOPS MY BAD and un-released it. I don't know if it was unintentional or not but the source is out there.
laptop$ pwd; ls
/home/user/src/winamp
BuildTools README.md cef_x86.bat vcpkg_version_finder.py
LICENSE.md Src install-packages.cmd winampAll_2019.sln
Qt automate-git.py vcpkg-ports