[Question] Extract .zdat files (from Mario Party)

Hello there,

So I've recently extracted all files from Mario Party Island Tour to get to the different music titles in there, however I came to another file extension before the actual music files now...

.zdat

However I've searched all around the web to find a way to extract them yet I can't really find one and 7zip fails to determind if or what archive this could be. My best guess now is that this is just another propriety thing Nintendo likes to do...

Does anyone know how to handle...

[Question] Extract .zdat files (from Mario Party)