It's not public domain, that's for sure. The debian/copyright file just says "mi.mp4" is copyright by the program's developer, which I'm sure that Famous Music would have something to say about: https://variety.com/2017/film/news/miss ... 202519677/
This was a concern of mine when I ported Hollywood from its PPA for MX Linux a couple years ago, so I replaced that file with some DFSG-safe dramatic music released under a Creative Commons license.