From 5c024025593a701df675842fe7136dbe23df59fb Mon Sep 17 00:00:00 2001
From: Milan Osztromok <tufa@polisys.hu>
Date: Thu, 16 Nov 2017 16:18:53 +0100
Subject: [PATCH 1/2] change robots.txt response content type to 'text/plain'

---
 app/code/Magento/Robots/Controller/Index/Index.php | 1 +
 1 file changed, 1 insertion(+)

diff --git a/app/code/Magento/Robots/Controller/Index/Index.php b/app/code/Magento/Robots/Controller/Index/Index.php
index b94626e93432d..679066d723dce 100644
--- a/app/code/Magento/Robots/Controller/Index/Index.php
+++ b/app/code/Magento/Robots/Controller/Index/Index.php
@@ -43,6 +43,7 @@ public function execute()
         /** @var Page $resultPage */
         $resultPage = $this->resultPageFactory->create(true);
         $resultPage->addHandle('robots_index_index');
+        $resultPage->setHeader('Content-Type', 'text/plain');
         return $resultPage;
     }
 }

From e9986c5ac7abdca30c20b416913c9458d974e5ad Mon Sep 17 00:00:00 2001
From: Ievgen Shakhsuvarov <ishakhsuvarov@magento.com>
Date: Fri, 17 Nov 2017 19:18:38 +0100
Subject: [PATCH 2/2] magento/magento2#12310: Fix robots.txt content type to
 'text/plain'

---
 .../Magento/Robots/Test/Unit/Controller/Index/IndexTest.php    | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/app/code/Magento/Robots/Test/Unit/Controller/Index/IndexTest.php b/app/code/Magento/Robots/Test/Unit/Controller/Index/IndexTest.php
index 22a69cc13bd52..d3a7a97c7ea80 100644
--- a/app/code/Magento/Robots/Test/Unit/Controller/Index/IndexTest.php
+++ b/app/code/Magento/Robots/Test/Unit/Controller/Index/IndexTest.php
@@ -51,6 +51,9 @@ public function testExecute()
         $resultPageMock->expects($this->once())
             ->method('addHandle')
             ->with('robots_index_index');
+        $resultPageMock->expects($this->once())
+            ->method('setHeader')
+            ->with('Content-Type', 'text/plain');
 
         $this->resultPageFactory->expects($this->any())
             ->method('create')