How to add a span before a tabs item?
Instead of adding a &lt;span&gt; element, you could also use the ::before CSS selector. If a combination with :first-child or :nth-child() is not helpful, most likely you have to implement hook_menu_local_tasks_alter() and add a specific class to the desired link(s) (you can add them through attributes in localized_options of the #link property, see https://api.drupal.org/comment/25393#comment-25393) and then you could use the ::before selector. Or you could implement/overwrite theme_menu_local_task() (probably in combination with a theme preprocess or the earlier mentioned alter function) to add your &lt;span&gt; element.