WordPress at a glance
function is not described

register_block_core_calendar() WP 1.0

Registers the core/calendar block on server.

No Hooks.

Return

Null. Nothing.

Usage

register_block_core_calendar();

Code of register_block_core_calendar() WP 5.5.1

<?php
function register_block_core_calendar() {
	register_block_type_from_metadata(
		__DIR__ . '/calendar',
		array(
			'render_callback' => 'render_block_core_calendar',
		)
	);
}