CC0 1.0 Universal (CC0 1.0) Public Domain Dedication

The person who associated a work with this deed has dedicated the work to
the public domain by waiving all of his or her rights to the work worldwide
under copyright law, including all related and neighboring rights, to the
extent allowed by law.

You can copy, modify, distribute, and perform the work, even for commercial
purposes, all without asking permission.

Full legal text: https://creativecommons.org/publicdomain/zero/1.0/legalcode
