[css-content-3] Inline attr() definition, since generic attr() was deferred from css-values.

Author: fantasai

css-content-3/Overview.bs

@@ -99,7 +99,7 @@ Inserting and replacing content with the 'content' property</h2>
 
 	<pre class='propdef'>
 		Name: content
-		Value: normal | none | [ <<content-replacement>> | <<content-list>> ] [/ [ <<string>> | <<counter>> ]+ ]?
+		Value: normal | none | [ <<content-replacement>> | <<content-list>> ] [/ [ <<string>> | <<counter>> | <<attr()>> ]+ ]?
 		Initial: normal
 		Applies To: all elements, tree-abiding pseudo-elements, and page margin boxes
 		Inherited: no
@@ -172,12 +172,16 @@ Inserting and replacing content with the 'content' property</h2>
 			Note: Replaced elements do not have ''::before'' or ''::after'' pseudo-elements;
 			the 'content' property replaces their entire contents.
 
+			ISSUE(2889): This value has historically been treated as <<content-list>> on ''::before'' and ''::after''.
+			Presumably there's a Web-compat requirement on this,
+			so these pseudo-elements might need an exception.
+
 		<dt><dfn type><<content-list>></dfn>
 		<dd>
 			Equal to:
 
 			<pre class=prod>
-			[ <<string>> | <<image>> | contents | <<quote>> | <<leader()>> | <<target>> | <<string()>> | <<content()>> | <<counter>> ]+
+			[ <<string>> | <<image>> | <<attr()>> | contents | <<quote>> | <<leader()>> | <<target>> | <<string()>> | <<content()>> | <<counter>> ]+
 			</pre>
 
 			Replaces the element's contents with one or more anonymous inline boxes
@@ -204,7 +208,7 @@ Inserting and replacing content with the 'content' property</h2>
 			Note: If the value of <<content-list>> is a single <<image>>,
 			it must instead be interpreted as a <<content-replacement>>.
 
-		<dt><dfn>/ [ <<string>> | <<counter>> ]+</dfn>
+		<dt><dfn>/ [ <<string>> | <<counter>> | <<attr()>> ]+</dfn>
 		<dd>
 			Specifies the "alt text" for the element.
 			See [[#alt]] for details.
@@ -275,7 +279,7 @@ Alternative Text for Accessibility</h3>
 
 
 <h3 id="strings">
-String</h3>
+Basic Strings: <<string>> and <<attr()>></h3>
 
 	<dl dfn-for="content, <content-list>" dfn-type=value>
 		<dt><dfn><<string>></dfn>
@@ -289,6 +293,18 @@ String</h3>
 			such as in ''content: "First  " "  Second";'',
 			which by default will render similar to <code>"First Second"</code>
 			(with a single visible space between the two words).
+
+		<dt><<attr()>>
+		<dd>
+			The <dfn noexport>attr()</dfn> functional notation represents
+			the string stored as the specified attribute’s value.
+			Its argument is a [=CSS qualified name=] (<code>qname</code>)
+			representing the attribute name and namespace, if any.
+			See [[!CSS3-NAMESPACE]].
+
+			Note: As in [[selectors-4#attrnmsp|attribute selectors]],
+			attribute names without an explicit namespace
+			do not associate with any default namespace.
 	</dl>
 
 <h3 id="content-uri">
@@ -1360,6 +1376,9 @@ bookmark-state</h3>
 			(<a href="https://github.com/w3c/csswg-drafts/issues/2038">Issue 2034</a>)
 		<li>Defined computed value of ''content: normal'' for ''::placeholder'' and ''::file-selector-button''.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/6124">Issue 6124</a>)
+		<li>Fixed an off-by-one error for the [=quote depth=] of closing quotes.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/2506">Issue 2506</a>)
+		<li>Inlined the definition of ''attr()'', since it has been dropped from [[CSS-VALUES-4]].
 		<li>Miscellaneous editorial spec clean up.
 	</ul>