revise popover related attribute mappings

this commit supersedes #446

TODO: finalize `popover` attribute mappings

index.html

@@ -5009,6 +5009,63 @@ <h3>HTML Attribute State and Property Mappings</h3>
               <td class="ax"><div class="general">Not mapped</div></td>
               <td class="comments"></td>
             </tr>
+            <tr tabindex="-1" id="att-popover">
+              <th>`popover`</th>
+              <td class="elements">
+                <a data-cite="html/popover.html#the-popover-attribute">`popover`</a>
+              </td>
+              <td class="aria"><div class="general">???</div></td>
+              <td class="ia2"><div class="general">???</div></td>
+              <td class="uia"><div class="general">???</div></td>
+              <td class="atk"><div class="general">???</div></td>
+              <td class="ax"><div class="general">???</div></td>
+              <td class="comments"></td>
+            </tr>
+            <tr tabindex="-1" id="att-popovertarget">
+              <th>`popovertarget`</th>
+              <td class="elements">
+              	<a data-cite="html/popover.html#attr-popovertarget">`button`</a>;
+                <a data-cite="html/popover.html#attr-popovertarget">`input type=button`</a>
+              </td>
+              <td class="aria"><div class="general">
+              	<p>
+                  If the associated element is displayed as a popover: 
+                  <a class="core-mapping" href="#ariaExpandedTrue">`aria-expanded=true`</a>
+                </p>
+              	<p>
+                  If the associated element is hidden: 
+                  <a class="core-mapping" href="#ariaExpandedFalse">`aria-expanded=false`</a>
+                </p>
+                <p>
+              	  If there is no associated element: 
+                  <a class="core-mapping" href="#ariaExpandedUndefined">`aria-expanded=undefined`</a>
+                </p>
+              </td>
+              <td class="ia2"><div class="general">Use WAI-ARIA mapping</div></td>
+              <td class="uia"><div class="general">Use WAI-ARIA mapping</div></td>
+              <td class="atk"><div class="general">Use WAI-ARIA mapping</div></td>
+              <td class="ax"><div class="general">Use WAI-ARIA mapping</div></td>
+              <td class="comments">
+                <p>
+                  If the associated element is not a direct sibling to the element with the `popovertarget` attribute in the DOM:
+                  create an <a class="core-mapping" href="#ariaDetalis">`aria-details`</a> relation with the associated element.
+                  Otherwise, there is no `aria-details` association.
+                </p>
+              </td>
+            </tr>
+            <tr tabindex="-1" id="att-popovertargetaction">
+              <th>`popovertargetaction`</th>
+              <td class="elements">
+              	<a data-cite="html/popover.html#attr-popovertargetaction">`button`</a>;
+                <a data-cite="html/popover.html#attr-popovertargetaction">`input type=button`</a>
+              </td>
+              <td class="aria"><div class="general">Not mapped</div></td>
+              <td class="ia2"><div class="general">Not mapped</div></td>
+              <td class="uia"><div class="general">Not mapped</div></td>
+              <td class="atk"><div class="general">Not mapped</div></td>
+              <td class="ax"><div class="general">Not mapped</div></td>
+              <td class="comments"></td>
+            </tr>
             <tr tabindex="-1" id="att-poster">
               <th>`poster`</th>
               <td class="elements">