That&#x27;s right.  The GPL depends on copyright to make it &quot;viral&quot;.  Some other licenses let you make changes and go proprietary, and they don&#x27;t really need copyright.  The MIT license, for example.[1]<p>[1] <a href="https:&#x2F;&#x2F;opensource.org&#x2F;licenses&#x2F;MIT" rel="nofollow">https:&#x2F;&#x2F;opensource.org&#x2F;licenses&#x2F;MIT</a>