Corrected the translation for comment tag

app/code/Magento/Paypal/etc/adminhtml/system/paypal_payflowpro_with_express_checkout.xml

@@ -6,7 +6,7 @@
  */
 -->
 <include xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_include.xsd">
-    <group id="paypal_payflowpro_with_express_checkout" translate="label comment" extends="payment_all_paypal/paypal_payflowpro">
+    <group id="paypal_payflowpro_with_express_checkout" translate="label" extends="payment_all_paypal/paypal_payflowpro">
         <label>Payflow Pro</label>
         <attribute type="paypal_ec_separate">0</attribute>
         <group id="paypal_payflow_required" translate="label" showInDefault="1" showInWebsite="1" sortOrder="10">
@@ -30,7 +30,7 @@
                     <field id="enable_paypal_payflow"/>
                 </requires>
             </field>
-            <field id="enable_express_checkout_bml_payflow" translate="label" type="select" sortOrder="21" showInWebsite="1" showInDefault="1">
+            <field id="enable_express_checkout_bml_payflow" translate="label comment" type="select" sortOrder="21" showInWebsite="1" showInDefault="1">
                 <label>Enable PayPal Credit</label>
                 <comment><![CDATA[PayPal Express Checkout Payflow Edition lets you give customers access to financing through PayPal Credit&#174; - at no additional cost to you.
                             You get paid up front, even though customers have more time to pay. A pre-integrated payment button lets customers pay quickly with PayPal Credit&#174;.

app/code/Magento/Paypal/i18n/en_US.csv

@@ -697,6 +697,11 @@ User,User
                                 The PayPal Advertising Program has been shown to generate additional purchases as well as increase consumer's average purchase sizes by 15%
                                 or more. <a href=""https://financing.paypal.com/ppfinportal/content/forrester"" target=""_blank"">See Details</a>.
                 "
+"PayPal Express Checkout Payflow Edition lets you give customers access to financing through PayPal Credit&#174; - at no additional cost to you.
+                            You get paid up front, even though customers have more time to pay. A pre-integrated payment button lets customers pay quickly with PayPal Credit&#174;.
+                            <a href=""https://www.paypal.com/webapps/mpp/promotional-financing"" target=""_blank"">Learn More</a>","PayPal Express Checkout Payflow Edition lets you give customers access to financing through PayPal Credit&#174; - at no additional cost to you.
+                            You get paid up front, even though customers have more time to pay. A pre-integrated payment button lets customers pay quickly with PayPal Credit&#174;.
+                            <a href=""https://www.paypal.com/webapps/mpp/promotional-financing"" target=""_blank"">Learn More</a>"
 "Customize Smart Buttons","Customize Smart Buttons"
 "Checkout Page","Checkout Page"
 "Label","Label"
@@ -731,4 +736,4 @@ User,User
 "PayPal will automatically display each enabled funding option to eligible buyers. For example, PayPal Credit is only shown to buyers in countries where PayPal Credit is offered and the currency offered by the merchant is USD.","PayPal will automatically display each enabled funding option to eligible buyers. For example, PayPal Credit is only shown to buyers in countries where PayPal Credit is offered and the currency offered by the merchant is USD."
 "PayPal Credit","PayPal Credit"
 "PayPal Guest Checkout Credit Card Icons","PayPal Guest Checkout Credit Card Icons"
-"Elektronisches Lastschriftverfahren - German ELV","Elektronisches Lastschriftverfahren - German ELV"
+"Elektronisches Lastschriftverfahren - German ELV","Elektronisches Lastschriftverfahren - German ELV"

dev/tests/integration/testsuite/Magento/Paypal/Model/Config/Structure/Reader/ConverterStub.php → dev/tests/integration/testsuite/Magento/Config/Model/Config/Structure/Reader/ConverterStub.php

@@ -3,14 +3,20 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-namespace Magento\Paypal\Model\Config\Structure\Reader;
+declare(strict_types=1);
+
+namespace Magento\Config\Model\Config\Structure\Reader;
+
+use Magento\Config\Model\Config\Structure\Converter;
 
 /**
- * Class ConverterStub
+ * Class ConverterStub used for ReaderTest.
  */
-class ConverterStub extends \Magento\Config\Model\Config\Structure\Converter
+class ConverterStub extends Converter
 {
     /**
+     * Convert dom document wrapper.
+     *
      * @param \DOMDocument $document
      * @return array|null
      */
@@ -20,7 +26,7 @@ public function getArrayData(\DOMDocument $document)
     }
 
     /**
-     * Convert dom document
+     * Convert dom document.
      *
      * @param \DOMNode $source
      * @return array

dev/tests/integration/testsuite/Magento/Paypal/Model/Config/Structure/Reader/ReaderStub.php → dev/tests/integration/testsuite/Magento/Config/Model/Config/Structure/Reader/ReaderStub.php

@@ -3,14 +3,20 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-namespace Magento\Paypal\Model\Config\Structure\Reader;
+declare(strict_types=1);
+
+namespace Magento\Config\Model\Config\Structure\Reader;
+
+use Magento\Config\Model\Config\Structure\Reader;
 
 /**
- * Class ReaderStub
+ * Class ReaderStub used for testing protected Reader::_readFiles() method.
  */
-class ReaderStub extends \Magento\Config\Model\Config\Structure\Reader
+class ReaderStub extends Reader
 {
     /**
+     * Wrapper for protected Reader::_readFiles() method.
+     *
      * @param array $fileList
      * @return array
      * @throws \Magento\Framework\Exception\LocalizedException

dev/tests/integration/testsuite/Magento/Config/Model/Config/Structure/Reader/ReaderTest.php

@@ -0,0 +1,146 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Config\Model\Config\Structure\Reader;
+
+use Magento\Config\Model\Config\SchemaLocator;
+use Magento\Framework\App\Utility\Files;
+use Magento\Framework\Config\Dom;
+use Magento\Framework\Config\FileResolverInterface;
+use Magento\Framework\Config\ValidationStateInterface;
+use Magento\Framework\ObjectManagerInterface;
+use Magento\Framework\View\TemplateEngine\Xhtml\CompilerInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+
+/**
+ * Class ReaderTest check Magento\Config\Model\Config\Structure\Reader::_readFiles() method.
+ */
+class ReaderTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * Test config location.
+     *
+     * @string
+     */
+    const CONFIG = '/dev/tests/integration/testsuite/Magento/Config/Model/Config/Structure/Reader/_files/';
+
+    /**
+     * @var ObjectManagerInterface
+     */
+    private $objectManager;
+
+    /**
+     * @var Files
+     */
+    private $fileUtility;
+
+    /**
+     * @var ValidationStateInterface
+     */
+    private $validationStateMock;
+
+    /**
+     * @var \Magento\Framework\Config\SchemaLocatorInterface
+     */
+    private $schemaLocatorMock;
+
+    /**
+     * @var FileResolverInterface
+     */
+    private $fileResolverMock;
+
+    /**
+     * @var ReaderStub
+     */
+    private $reader;
+
+    /**
+     * @var ConverterStub
+     */
+    private $converter;
+
+    /**
+     * @var CompilerInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $compiler;
+
+    /**
+     * @inheritdoc
+     */
+    protected function setUp()
+    {
+        $this->objectManager = Bootstrap::getObjectManager();
+        $this->fileUtility = Files::init();
+
+        $this->validationStateMock = $this->getMockBuilder(ValidationStateInterface::class)
+            ->setMethods(['isValidationRequired'])
+            ->getMockForAbstractClass();
+        $this->schemaLocatorMock = $this->getMockBuilder(SchemaLocator::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['getPerFileSchema'])
+            ->getMock();
+        $this->fileResolverMock = $this->getMockBuilder(FileResolverInterface::class)
+            ->getMockForAbstractClass();
+
+        $this->validationStateMock->expects($this->atLeastOnce())
+            ->method('isValidationRequired')
+            ->willReturn(false);
+        $this->schemaLocatorMock->expects($this->atLeastOnce())
+            ->method('getPerFileSchema')
+            ->willReturn(false);
+
+        $this->converter = $this->objectManager->create(ConverterStub::class);
+
+        //Isolate test from actual configuration, and leave only sample data.
+        $this->compiler = $this->getMockBuilder(CompilerInterface::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['compile'])
+            ->getMockForAbstractClass();
+
+        $this->reader = $this->objectManager->create(
+            ReaderStub::class,
+            [
+                'fileResolver' => $this->fileResolverMock,
+                'converter' => $this->converter,
+                'schemaLocator' => $this->schemaLocatorMock,
+                'validationState' => $this->validationStateMock,
+                'fileName' => 'no_existing_file.xml',
+                'compiler' => $this->compiler,
+                'domDocumentClass' => Dom::class
+            ]
+        );
+    }
+
+    /**
+     * The test checks the file structure after processing the nodes responsible for inserting content.
+     *
+     * @return void
+     */
+    public function testXmlConvertedConfigurationAndCompereStructure()
+    {
+        $actual = $this->reader->readFiles(['actual' => $this->getContent()]);
+
+        $document = new \DOMDocument();
+        $document->loadXML($this->getContent());
+
+        $expected = $this->converter->getArrayData($document);
+
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * Get config sample data for test.
+     *
+     * @return string
+     */
+    protected function getContent()
+    {
+        $files = $this->fileUtility->getFiles([BP . static::CONFIG], 'config.xml');
+
+        return file_get_contents(reset($files));
+    }
+}