I used this for years, from version 1.9 all the way to 5.x when I moved onto other software.
EDIT: Here is the full press release.
Press Release- Inside information May 16, 2024 – 08:30 CEST Winamp has announced that it is opening up its source code to enable collaborative development of its legendary player for Windows. Winamp has announced that on 24 September 2024, the application's source code will be open to developers worldwide. Winamp will open up its code for the player used on Windows, enabling the entire community to participate in its development. This is an invitation to global collaboration, where developers worldwide can contribute their expertise, ideas, and passion to help this iconic software evolve. Winamp has become much more than just a music player. It embodies a unique digital culture, aesthetic, and user experience. With this initiative to open the source code, Winamp is taking the next step in its history, allowing its users to contribute directly to improving the product. "This is a decision that will delight millions of users around the world. Our focus will be on new mobile players and other platforms. We will be releasing a new mobile player at the beginning of July. Still, we don't want to forget the tens of millions of users who use the software on Windows and will benefit from thousands of developers' experience and creativity. Winamp will remain the owner of the software and will decide on the innovations made in the official version," explains Alexandre Saboundjian, CEO of Winamp. Interested developers can now make themselves known at the following address: about.winamp.com/free-llama
Indeed, but as I've been saying in other comments, that doesn't mean the license will be FOSS. The press release is vague, and I think that’s likely to be intentional ambiguity.