It's not enough to only look at the css files, js files and classes that drupal loads

Menus

All menus are wrapped in a <nav> - HTML5-style - instead of the <div>
including the awesome menu-block module

Book

Markup & CSS cleaned up (the same as in Drupal8)

• book-navigation.tpl.php
• aggregator-item.tpl.php
• block.tpl.php
• comment-wrapper.tpl.php
• comment.tpl.php
• eva-display-entity-view.tpl.php
• field.tpl.php
• html.tpl.php
• menu-block-wrapper.tpl.php
• node--nodeblock.tpl.php
• node.tpl.php
• page.tpl.php
• region.tpl.php
• taxonomy-term.tpl.php
• views-view-list.tpl.php
• views-view.tpl.php
• html.tpl
• page.tpl
• node.tpl
• comments.tpl