WordPress at a glance
action is not described

rest_delete_user action-hook . WP 4.7.0

Fires immediately after a user is deleted via the REST API.

Usage

add_action( 'rest_delete_user', 'action_function_name_5189', 10, 3 );
function action_function_name_5189( $user, $response, $request ){
	// action...
}
$user(WP_User)
The user data.
$response(WP_REST_Response)
The response returned from the API.
$request(WP_REST_Request)
The request sent to the API.

Where the hook is called

WP_REST_Users_Controller::delete_item()
wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php 809
do_action( 'rest_delete_user', $user, $response, $request );

Where the hook is used (in WP core)

Does not used.