WordPress at a glance
action is not described

wp_footer action-hook . WP 1.5.1

Prints scripts or data before the closing body tag on the front end.

Usage

add_action( 'wp_footer', 'action_function_name_8555' );
function action_function_name_8555(){
	// action...
}

Where the hook is called

wp_footer()
wp_footer
wp-includes/general-template.php 2630
do_action( 'wp_footer' );

Where the hook is used (in WP core)

wp-includes/customize/class-wp-customize-selective-refresh.php 173
add_action( 'wp_footer', array( $this, 'export_preview_data' ), 1000 );
wp-includes/class-wp-customize-widgets.php 1060
add_action( 'wp_footer', array( $this, 'export_preview_data' ), 20 );
wp-includes/default-filters.php 287
add_action( 'wp_footer', 'wp_print_footer_scripts', 20 );
wp-includes/default-filters.php 522
add_action( 'wp_footer', 'wp_admin_bar_render', 1000 );
wp-includes/class-wp-customize-nav-menus.php 1180
add_filter( 'wp_footer', array( $this, 'export_preview_data' ), 1 );
wp-includes/media.php 1875
add_action( 'wp_footer', 'wp_underscore_playlist_templates', 0 );
wp-includes/media.php 3655
add_action( 'wp_footer', 'wp_print_media_templates' );
wp-includes/class-wp-customize-manager.php 1861
add_action( 'wp_footer', array( $this, 'customize_preview_settings' ), 20 );