reverted:
--- b/core/install.php
+++ a/core/install.php
@@ -7,9 +7,7 @@
 
 // Change the directory to the Drupal root.
 chdir('..');
+
-error_reporting(E_ALL);
-ini_set('display_errors', TRUE);
-ini_set('display_startup_errors', TRUE);
 /**
  * Global flag to indicate the site is in installation mode.
  *
reverted:
--- b/index.php
+++ a/index.php
@@ -16,10 +16,6 @@
 
 $autoloader = require_once __DIR__ . '/core/vendor/autoload.php';
 
-error_reporting(E_ALL);
-ini_set('display_errors', TRUE);
-ini_set('display_startup_errors', TRUE);
-
 try {
 
   $request = Request::createFromGlobals();