Add a hreftranslate attribute

Proposal from https://github.com/dtapuska/html-translate

Fixes 2945

source

@@ -19422,6 +19422,7 @@ interface <dfn>HTMLDivElement</dfn> : <span>HTMLElement</span> {};</code></pre>
    <dd><code data-x="attr-hyperlink-ping">ping</code></dd>
    <dd><code data-x="attr-hyperlink-rel">rel</code></dd>
    <dd><code data-x="attr-hyperlink-hreflang">hreflang</code></dd>
+   <dd><code data-x="attr-hyperlink-hreftranslate">hreftranslate</code></dd>
    <dd><code data-x="attr-hyperlink-type">type</code></dd>
    <dd><code data-x="attr-hyperlink-referrerpolicy">referrerpolicy</code></dd>
    <dt><span data-x="concept-element-dom">DOM interface</span>:</dt>
@@ -19435,6 +19436,7 @@ interface <dfn>HTMLAnchorElement</dfn> : <span>HTMLElement</span> {
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-a-rel">rel</span>;
   [SameObject, PutForwards=<span data-x="dom-DOMTokenList-value">value</span>] readonly attribute <span>DOMTokenList</span> <span data-x="dom-a-relList">relList</span>;
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-a-hreflang">hreflang</span>;
+  [<span>CEReactions</span>] attribute DOMString <span data-x="dom-a-hreftranslate">hreftranslate</span>;
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-a-type">type</span>;
 
   [<span>CEReactions</span>] attribute DOMString <span data-x="dom-a-text">text</span>;
@@ -19461,8 +19463,10 @@ interface <dfn>HTMLAnchorElement</dfn> : <span>HTMLElement</span> {
   <p>The <code data-x="attr-hyperlink-target">target</code>, <code
   data-x="attr-hyperlink-download">download</code>, <code data-x="attr-hyperlink-ping">ping</code>,
   <code data-x="attr-hyperlink-rel">rel</code>, <code
-  data-x="attr-hyperlink-hreflang">hreflang</code>, <code data-x="attr-hyperlink-type">type</code>,
-  and <code data-x="attr-hyperlink-referrerpolicy">referrerpolicy</code> attributes must be omitted
+  data-x="attr-hyperlink-hreflang">hreflang</code>, <code
+  data-x="attr-hyperlink-hreftranslate">hreftranslate</code>, <code
+  data-x="attr-hyperlink-type">type</code>, and <code
+  data-x="attr-hyperlink-referrerpolicy">referrerpolicy</code> attributes must be omitted
   if the <code data-x="attr-hyperlink-href">href</code> attribute is not present.</p>
 
   <p>If the <code data-x="attr-itemprop">itemprop</code> attribute is specified on an <code>a</code> element,
@@ -19562,6 +19566,11 @@ interface <dfn>HTMLAnchorElement</dfn> : <span>HTMLElement</span> {
   data-x="dom-a-type">type</code></dfn>, must <span>reflect</span> the respective content attributes
   of the same name.</p>
 
+  <p>The IDL attribute <dfn><code data-x="dom-a-hreftranslate">hreftranslate</code></dfn> must
+  <span>reflect</span> the <code data-x="attr-hyperlink-hreftranslate">hrefttranslate</code>
+  content attribute. If the UA does not support a client side translation service this attribute
+  must not be supported.</p>
+
   <p>The IDL attribute <dfn><code data-x="dom-a-rellist">relList</code></dfn> must
   <span>reflect</span> the <code data-x="attr-hyperlink-rel">rel</code> content attribute.</p>
 
@@ -22533,6 +22542,14 @@ document.body.appendChild(wbr);</code></pre>
   associated with the resource to determine its language, not metadata included in the link to the
   resource.</span></p>
 
+  <p>The <dfn><code data-x="attr-hyperlink-hreftranslate">hreftranslate</code></dfn> attribute on
+  <code>a</code> elements that create <span data-x="hyperlink">hyperlinks</span>, if present,
+  provides the desired translation language of the linked resource. The value must be a valid BCP 47
+  language tag. <ref spec=BCP47> When nativating the anchor, user agents that support client side
+  translation should invoke the translation engine providing the value of the attribute.
+  User agents that do not have a client side translation must not support this attribute
+  so that feature detection of this feature is possible.</p>
+
   <p>The <dfn><code data-x="attr-hyperlink-type">type</code></dfn> attribute, if present, gives the
   <span>MIME type</span> of the linked resource. It is purely advisory. The value must be a
   <span>valid MIME type string</span>. <span w-nodev>User agents must not consider the <code
@@ -117981,6 +117998,11 @@ interface <dfn>External</dfn> {
           <code data-x="attr-link-hreflang">link</code>
      <td> Language of the linked resource
      <td> Valid BCP 47 language tag
+    <tr>
+     <th> <code data-x="">hreftranslate</code>
+     <td> <code data-x="attr-hyperlink-hreftranslate">a</code>
+     <td> Desired language of the linked resource
+     <td> Valid BCP 47 language tag
     <tr>
      <th> <code data-x="">http-equiv</code>
      <td> <code data-x="attr-meta-http-equiv">meta</code>