Index: src/wp-includes/functions.php
===================================================================
--- src/wp-includes/functions.php	(revision 47069)
+++ src/wp-includes/functions.php	(working copy)
@@ -3511,8 +3511,49 @@
 	</style>
 </head>
 <body id="error-page">
-<?php endif; // ! did_action( 'admin_head' ) ?>
-	<?php echo $message; ?>
+<?php endif; // ! did_action( 'admin_head' )
+
+	global $upgrading;
+	if( ( time() - $upgrading ) <= 600 ) { 
+		__( '&laquo; Back' ); 
+		?>
+		<div class="wp-die-message">
+			<p><?php echo $message; ?></p>
+			<p id="automatic" style="display:none"><?php echo __( 'This page will automatically reload every ten seconds.' ); ?></p>
+			<p id="manual"><?php echo __( 'Please try again in a minute.' ); ?></p>
+			<p id="waiting" style="display:none"><?php echo __( 'Waiting...' ); ?></p>
+			<p id="soon" style="display:none"><?php echo __( 'Will reload soon...' ); ?></p>
+		</div>
+
+		<script type='text/javascript'>
+			function sleep(ms) {
+				return new Promise(resolve => setTimeout(resolve, ms));
+			}
+
+			async function refreshAfterPause() {
+				// Pause to allow the page to fully load.
+				await sleep(100);
+
+				// Fill the relevant prompts, only if Javascript is enabled.
+				document.getElementById('automatic').style = 'display:block';
+				document.getElementById('manual').style = 'display:none';
+				document.getElementById('waiting').style = 'display:block';
+
+				await sleep(7000);
+
+				// Show that the page is about to reload
+				document.getElementById('waiting').style = 'display:none';
+				document.getElementById('soon').style = 'display:block';
+
+				await sleep(3000);			
+				window.location.reload(true);
+			}
+
+			refreshAfterPause();
+		</script>
+	<?php } else { 
+		echo $message; 
+	} ?>
 </body>
 </html>
 	<?php
Index: src/wp-includes/load.php
===================================================================
--- src/wp-includes/load.php	(revision 47069)
+++ src/wp-includes/load.php	(working copy)
@@ -226,7 +226,7 @@
 	header( 'Retry-After: 600' );
 
 	wp_die(
-		__( 'Briefly unavailable for scheduled maintenance. Check back in a minute.' ),
+		__( 'Briefly unavailable for scheduled maintenance.' ),
 		__( 'Maintenance' ),
 		503
 	);
