Document default content-footer

README.md

@@ -161,7 +161,11 @@ rendered inside an `<article>...</article>` block element.
 This block provides a footer for the page, which renders within the 
 `<footer></footer>` block at the end of the `<main></main>` section.
 
-Default content-footer definitions are not yet implemented.
+The default content-footer blocks for the homepage and for list pages 
+implement pagination controls to show the content summaries a page at a time.
+
+The default content-footer block for single pages displays previous and/or
+next in section links.
 
 #### footer