WordPress at a glance
action is not described

customize_save action-hook . WP 3.4.0

Fires once the theme has switched in the Customizer, but before settings have been saved.

Usage

add_action( 'customize_save', 'action_function_name_5435' );
function action_function_name_5435( $manager ){
	// action...
}
$manager(WP_Customize_Manager)
WP_Customize_Manager instance.

Where the hook is called

WP_Customize_Manager::_publish_changeset_values()
customize_save
wp-includes/class-wp-customize-manager.php 3358
do_action( 'customize_save', $this );

Where the hook is used (in WP core)

Does not used.