Copyright attribute as global attribute

We could have a copyright attribute, with a link to the licence, could be useful for giving extra information to plugins or external sites.

<img src="landscape.jpg" copyright="https://creativecommons.org/licenses/by/2.0/" alt="landscape" />

Not only for images, but for all elements. Like articles or code blocks.

<pre><code copyright="http://opensource.org/licenses/cpl1.0.php">
  if (false) {
    var foo = "bar";
  }
</code></pre>

Why?

External sites or plugins could make use of it when checking images or articles if they are allowed to use it.

Aren’t there already RDF attributes for this?

That’s true, I forgot about that.

How can I close it?