CC0 1.0 Universal

The author of the source collection has dedicated the included music to the
public domain under CC0 1.0 Universal. To the extent the author holds copyright
and related rights in the included material, those rights are waived worldwide
to the fullest extent permitted by law.

https://creativecommons.org/publicdomain/zero/1.0/

Source: drakzlin, "music loops" (OpenGameArt.org)
https://opengameart.org/content/music-loops-0

The source author states that the collection contains simple game-music loops
and identifies the files as WAV/MP3. No attribution is required by CC0; source
credit is included here for provenance.