Index: src/wp-includes/functions.php
===================================================================
--- src/wp-includes/functions.php	(revision 42227)
+++ src/wp-includes/functions.php	(working copy)
@@ -5766,6 +5766,10 @@
 		return;
 	}
 
+	if ( '.example' === substr( $old_email, -8 ) ) {
+		return;
+	}
+
 	/* translators: Do not translate OLD_EMAIL, NEW_EMAIL, SITENAME, SITEURL: those are placeholders. */
 	$email_change_text = __( 'Hi,
 
Index: src/wp-includes/ms-functions.php
===================================================================
--- src/wp-includes/ms-functions.php	(revision 42227)
+++ src/wp-includes/ms-functions.php	(working copy)
@@ -2678,6 +2678,10 @@
 		return;
 	}
 
+	if ( '.example' === substr( $old_email, -8 ) ) {
+		return;
+	}
+
 	/* translators: Do not translate OLD_EMAIL, NEW_EMAIL, SITENAME, SITEURL: those are placeholders. */
 	$email_change_text = __( 'Hi,
 
Index: src/wp-admin/includes/schema.php
===================================================================
--- src/wp-admin/includes/schema.php	(revision 42227)
+++ src/wp-admin/includes/schema.php	(working copy)
@@ -398,7 +398,7 @@
 	/* translators: site tagline */
 	'blogdescription' => __('Just another WordPress site'),
 	'users_can_register' => 0,
-	'admin_email' => 'you@example.com',
+	'admin_email' => 'you@your.domain.example',
 	/* translators: default start of the week. 0 = Sunday, 1 = Monday */
 	'start_of_week' => _x( '1', 'start of week' ),
 	'use_balanceTags' => 0,