The description of aria-hidden has the following text:

https://www.w3.org/TR/wai-aria-1.2/#aria-hidden
An element is considered hidden if it, or any of its ancestors are not rendered or have their aria-hidden attribute value set to true.

This would suggest that if I do something like the following, my list would be empty, because the li is hidden.

  <ul aria-owns="li"></ul>
  <div aria-hidden="true">
    <li id="li">Child node</li>
  </div>

This doesn't seem to be the case when testing in Chrome and Firefox. There it seems that aria-owns is taking priority over aria-hidden. Intuitively, that does make sense to me. So then that makes me wonder whether that phrase in aria-hidden should be changed to maybe something like:

An element is considered hidden if it, or any of its ancestors are not rendered**, or if any of its Owner Elements** have their aria-hidden attribute value set to true.