WordPress at a glance
action is not described

delete_option_(option) action-hook . WP 3.0.0

Fires after a specific option has been deleted.

The dynamic portion of the hook name, $option, refers to the option name.

Usage

add_action( 'delete_option_(option)', 'action_function_name_5425' );
function action_function_name_5425( $option ){
	// action...
}
$option(string)
Name of the deleted option.

Where the hook is called

delete_option()
wp-includes/option.php 578
do_action( "delete_option_{$option}", $option );

Where the hook is used (in WP core)

Does not used.