App Passwords: Explain that apps can access to all sites in a network.

Props georgestephanis, spacedmonkey, johnjamesjacoby, SergeyBiryukov, marybaum.
Fixes #51489.


git-svn-id: https://develop.svn.wordpress.org/trunk@49270 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/authorize-application.php

@@ -121,6 +121,30 @@ require_once ABSPATH . 'wp-admin/admin-header.php';
 			<p><?php _e( 'Would you like to give this application access to your account? You should only do this if you trust the app in question.' ); ?></p>
 		<?php endif; ?>
 
+		<?php
+		if ( is_multisite() ) {
+			$blogs = get_blogs_of_user( $user->ID, true );
+			if ( count( $blogs ) > 1 ) {
+				?>
+				<p>
+				<?php
+					printf(
+						/* translators: 1: url to my-sites.php, 2: Number of blogs the user has. */
+						_n(
+							'This will grant access to <a href="%1$s">the %2$s blog in this installation that you have permissions on</a>.',
+							'This will grant access to <a href="%1$s">all %2$s blogs in this installation that you have permissions on</a>.',
+							count( $blogs )
+						),
+						admin_url( 'my-sites.php' ),
+						number_format_i18n( count( $blogs ) )
+					);
+				?>
+				</p>
+				<?php
+			}
+		}
+		?>
+
 		<?php if ( $new_password ) : ?>
 			<div class="notice notice-success notice-alt below-h2">
 				<p class="password-display">