pre-upload-ui action-hook . WP 2.6.0

Fires just before the legacy (pre-3.5.0) upload interface is loaded.

Usage

add_action( 'pre-upload-ui', 'action_function_name_6594' );
function action_function_name_6594(){
	// action...
}

Where the hook is called

do_action( 'pre-upload-ui' );

do_action( 'pre-upload-ui' );

Where the hook is used (in WP core)