WordPress at a glance
action is not described

wp_print_styles action-hook . WP 2.6.0

Fires before styles in the $handles queue are printed.

Usage

add_action( 'wp_print_styles', 'action_function_name_3528' );
function action_function_name_3528(){
	// action...
}

Where the hook is called

wp_print_styles()
wp-includes/functions.wp-styles.php 52
do_action( 'wp_print_styles' );

Where the hook is used (in WP core)

wp-includes/class-wp-customize-widgets.php 1059
add_action( 'wp_print_styles', array( $this, 'print_preview_css' ), 1 );
wp-includes/default-filters.php 293
add_action( 'wp_print_styles', 'print_emoji_styles' );