Add the current site ID to the Admin Bar

admin-bar-site-id.php

<?php
/**
 *	Plugin Name: Admin Bar Site ID
 *	Description: Add the current site ID to the Admin Bar
 *	Version:     1.0.3
 *	Author:      James Morrison
 *	Author URI:  https://www.jamesmorrison.me/
 **/


/**
 * Security Check
 *
 * @since 1.0.0
 **/

defined( 'ABSPATH' ) or die();


/**
 * Add Site ID to admin bar
 *
 * @since 1.0.0
 **/

add_action( 'admin_bar_menu',
	function( $wp_admin_bar ) {
	
		// Sanity check - this won't work if this isn't a multisite or if the user can't access network admin
		if ( ! is_multisite() || ! current_user_can( 'manage_network' ) ) {
			return;
		}
	
		// Get the Site ID
		$_site_id = get_current_blog_id();
	
		// Add the Node
		$wp_admin_bar->add_node( [
			"id"    => "site-id",
			"title" => "Site ID: $_site_id"
			"href"  => esc_url( add_query_arg( 'id', $_site_id, network_admin_url( 'site-info.php' ) ) ),
		] );

	},
999, 1 );