cc0 = creative common 0 which means its part of public domain. Here&#x27;s an explanation: <a href="https:&#x2F;&#x2F;creativecommons.org&#x2F;about&#x2F;cc0" rel="nofollow">https:&#x2F;&#x2F;creativecommons.org&#x2F;about&#x2F;cc0</a>