Add rest route for alt api check

wp-admin/includes/class-wp-site-health.php

@@ -1397,7 +1397,7 @@ class WP_Site_Health {
 	}
 
 	/**
-	 * Tests if the site can communicate with WordPress.org.
+	 * Tests if the site can communicate with a non-default update API endpoint.
 	 *
 	 * @since 6.8.0
 	 *

wp-includes/rest-api/endpoints/class-wp-rest-site-health-controller.php

@@ -124,6 +124,25 @@ class WP_REST_Site_Health_Controller extends WP_REST_Controller {
 			)
 		);
 
+		register_rest_route(
+			$this->namespace,
+			sprintf(
+				'/%s/%s',
+				$this->rest_base,
+				'alt-update-api-communication'
+			),
+			array(
+				array(
+					'methods' => 'GET',
+					'callback' => array( $this, 'test_alt_update_api_communication' ),
+					'permission_callback' => function() {
+						return $this->validate_request_permission( 'dotorg_communication' );
+					},
+				),
+				'schema' => array( $this, 'get_public_item_schema' ),
+			)
+		);
+
 		register_rest_route(
 			$this->namespace,
 			sprintf(