Major changes! Zen now allows subthemes to define their own node.tpl.php, node-type.tpl.php, block-type.tpl.php, page-loc.tpl.php, etc... Also rearranging the way that secondary style sheets are included as per #113184.

several changes including new background image for unpublished items, microformat for node creation dates, new classes for comment-by-author, comment-by-anon, node-mine, comment-mine. other minor changes

Modified the help text to be more succinct and easier to understand.  Modified the breadcrumb to be a double colon because the long arrow looks awkward.  Changed the _phptemplate_variables to be a semi-useful example instead of a giant block that is commented out.  I am still uncomfortable with this file as it went from a very tiny file to an extremely verbose one. I'm recommending trimming it even more, if not just providing a link to an example template.php file posted on drupal.org with more thorough documentation.

significantly improved template.php, with lots of documention, comments, and some simple examples of useful theming tricks

See #81217 for more.