WordPress at a glance
action is not described

unload_textdomain action-hook . WP 3.0.0

Fires before the text domain is unloaded.

Usage

add_action( 'unload_textdomain', 'action_function_name_5687' );
function action_function_name_5687( $domain ){
	// action...
}
$domain(string)
Text domain. Unique identifier for retrieving translated strings.

Where the hook is called

unload_textdomain()
wp-includes/l10n.php 686
do_action( 'unload_textdomain', $domain );

Where the hook is used (in WP core)

Does not used.