Register post meta of an array of integers.

register-meta-array-int.php

<?php

register_post_meta(
			'post',
			'forage_authors',
			[
				'type'              => 'array',
				'description'       => 'Additional authors IDs.',
				'single'            => true,
				'sanitize_callback' => null,
				'show_in_rest'      => [
					'schema' => [
						'type'  => 'array',
						'items' => [
							'type' => 'number',
						],
					],
				],
			]
		);