Add a core/requirements module.

js/core/requirements.js

@@ -0,0 +1,57 @@
+// Module core/requirements
+// This module does two things:
+//
+// 1.  It finds and marks all requirements. These are elements with class "req".
+//     When a requirement is found, it is reported using the "req" event. This
+//     can be used by a containing shell to extract them.
+//     Requirements are automatically numbered.
+//
+// 2.  It allows referencing requirements by their ID simply using an empty <a>
+//     element with its href pointing to the requirement it should be referencing
+//     and a class of "reqRef".
+
+define(
+    [],
+    function () {
+        return {
+            run: function (conf, doc, cb, msg) {
+                msg.pub("start", "core/requirements");
+
+                $("*.req").each(function (i) {
+                    i++;
+                    var $req = $(this)
+                    ,   title = "Req. " + i
+                    ;
+                    msg.pub("req", {
+                      type: "req",
+                      number: i,
+                      content: $req.html(),
+                      title: title
+                    });
+                    $req.prepend("<a href='#" + $req.attr("id") + "'>" + title + "</a>: ");
+                });
+
+                $("a.reqRef").each(function () {
+                    var $ref = $(this)
+                    ,   href = $ref.attr("href")
+                    ,   id
+                    ,   $req
+                    ,   txt
+                    ;
+                    if (!href) return;
+                    id = href.substring(1);
+                    $req = $("#" + id);
+                    if ($req.length) {
+                      txt = $req.find("> a").text();
+                    } else {
+                      txt = "Req. not found '" + id + "'";
+                    }
+                    $ref.text(txt);
+                });
+
+                msg.pub("end", "core/requirements");
+                cb();
+            }
+        };
+    }
+);

js/profile-w3c-common.js

@@ -15,6 +15,7 @@ define([
         ,   "core/dfn"
         ,   "core/examples"
         ,   "core/issues-notes"
+        ,   "core/requirements"
         ,   "core/highlight"
         ,   "core/best-practices"
         ,   "core/figures"