Add release notes for Sumac Header frontend plugin slots

source/community/release_notes/sumac/customizing_header.rst

@@ -1,8 +1,60 @@
-Customizing Site Header and Learner Dashboard
-#############################################
+Customizing Site Header Using Frontend "Slots"
+##############################################
 
-Coming soon in Sumac: leverage *frontend plugin slots* to quickly and easily
-modify visual elements on the site header and on the Learner Dashboard. Be sure
-to watch this page for more detail!
+Utilizing *frontend plugin slots*, site operators now have the ability to
+customize various portions of the site header.
 
-The Open edX Sumac release comes out in December 2024.
+A “frontend plugin slot” refers to an area of a web page - comprising one or
+more visual elements - that can be “swapped out” with other visual elements. For
+example, one new plugin slot allows you to remove the "Help" button in the header.
+
+Overhead and hassle is minimized using the plugin slot system. Site operators
+can leverage a plugin slot using a configuration file; the codebase does not
+need to be copied (“forked”) nor are extensive changes needed. A snippet of code
+is all that is needed to use a plugin slot. A site operator places that code
+within a configuration file. Site operators should refer to the src/plugin-slots
+directory within each MFE's codebase to view documentation for that MFE's plugin
+slot(s).
+
+In these release notes, we'll cover three example use cases for the header. Full
+documentation is available `within the frontend-component-header codebase
+<https://github.com/openedx/frontend-component-header/tree/master/src/plugin-slots>`_.
+
+.. contents::
+  :local:
+  :depth: 1
+
+Simple example: Removing help button
+************************************
+
+In the default learner dashboard, the default content contains a "Help" button
+to the left of the logged in user's username:
+
+   .. image:: /_images/release_notes/sumac/sumac-header-easy-before.png
+
+With frontend plugin slots, you can now hide the "Help" button:
+
+   .. image:: /_images/release_notes/sumac/sumac-header-easy-after.png
+
+For site operators, here is a sample of the `env.config.jsx` file used to hide
+the the content:
+
+.. toggle::
+
+    .. code-block:: javascript
+
+        import { PLUGIN_OPERATIONS } from '@openedx/frontend-plugin-framework';
+
+        const config = {
+          pluginSlots: {
+            learning_help_slot: {
+              plugins: [
+                {
+                  op: PLUGIN_OPERATIONS.Hide,
+                },
+              ]
+            },
+          },
+        }
+
+        export default config;