Problem/Motivation
\Drupal\ckeditor5\HTMLRestrictions::getTextContainerElementList provides list of text-container elements. On top of the elements included in the list, <td> and <li> are able to act as text-container elements in the sense that text can be rendered inside the element without wrapping the text with a <p> or <div>. However, these elements are not able to render attributes usually rendered on text-container elements. For this reason we should not consider them as text-container elements.
Proposed resolution
Document the <td> and <li> that are special case text-containers in \Drupal\ckeditor5\HTMLRestrictions::getTextContainerElementList.