do_action( 'wp_head' )
Prints scripts or data in the head tag on the front end.
The wp_head action hook is triggered within the
<head></head> section of the theme’s
header.php template by the
WordPress core uses this hook to perform many actions. Most of default actions into the 'wp-head' hook by WordPress core are set up in
wp-includes/default-filters.php. If you need to remove a default hook, this file will give you the priority for which to use to remove the hook.