A quick overview of drupal theming
Helps make sense of all the HTML/PHP files
template.php
One of the most useful files when creating or modifying Drupal themes
block--no-wrapper.tpl.php
Returns the HTML for a block
block.tpl.php
Returns the HTML for a block
comment-wrapper.tpl.php
Returns the HTML for a wrapping container around comments
comment.tpl.php
Returns the HTML for comments
html.tpl.php
Returns the HTML for the basic html structure of a single Drupal page
maintenance-page.tpl.php
Returns the HTML for a single Drupal page while offline
node.tpl.php
Returns the HTML for a node
page.tpl.php
Returns the HTML for a single Drupal page
pane-header.tpl.php
Returns the HTML for Panels Everywhere's navigation pane
pane-messages.tpl.php
Returns the HTML for Panels Everywhere's messages pane
pane-navigation.tpl.php
Returns the HTML for Panels Everywhere's navigation pane
panelizer-view-mode.tpl.php
This file is only in Zen 7.x-3.x
panels-pane.tpl.php
Returns the HTML for a Panels pane
region--footer.tpl.php
Returns the HTML for the footer region
region--no-wrapper.tpl.php
Returns the HTML for region with bare minimum HTML
region--sidebar.tpl.php
This file is only in Zen 7.x-3.x
region.tpl.php
Returns HTML for a region
user-picture.tpl.php
Returns HTML for the user’s picture