register_block_core_site_icon_setting

Register a core site setting for a site icon

function register_block_core_site_icon_setting() {
	register_setting(
		'general',
		'site_icon',
		array(
			'show_in_rest' => true,
			'type'         => 'integer',
			'description'  => __( 'Site icon.' ),
		)
	);
}