diff --git a/core/lib/Drupal/Component/Render/EscapedMarkup.php b/core/lib/Drupal/Component/Render/EscapableString.php
similarity index 83%
rename from core/lib/Drupal/Component/Render/EscapedMarkup.php
rename to core/lib/Drupal/Component/Render/EscapableString.php
index a6fd863..eb44f16 100644
--- a/core/lib/Drupal/Component/Render/EscapedMarkup.php
+++ b/core/lib/Drupal/Component/Render/EscapableString.php
@@ -2,7 +2,7 @@
 
 /**
  * @file
- * Contains \Drupal\Component\Render\EscapedMarkup.
+ * Contains \Drupal\Component\Render\EscapableString.
  */
 
 namespace Drupal\Component\Render;
@@ -15,7 +15,7 @@
  *
  * @ingroup sanitization
  */
-class EscapedMarkup implements EscapedMarkupInterface {
+class EscapableString implements EscapableStringInterface {
 
   /**
    * The string to escape.
@@ -25,7 +25,7 @@ class EscapedMarkup implements EscapedMarkupInterface {
   protected $string;
 
   /**
-   * Constructs an EscapedMarkup object.
+   * Constructs an EscapableString object.
    *
    * @param $string
    *   The string to escape. This value will be cast to a string.
diff --git a/core/lib/Drupal/Component/Render/EscapedMarkupInterface.php b/core/lib/Drupal/Component/Render/EscapableStringInterface.php
similarity index 55%
rename from core/lib/Drupal/Component/Render/EscapedMarkupInterface.php
rename to core/lib/Drupal/Component/Render/EscapableStringInterface.php
index 7efc291..eb1d63f 100644
--- a/core/lib/Drupal/Component/Render/EscapedMarkupInterface.php
+++ b/core/lib/Drupal/Component/Render/EscapableStringInterface.php
@@ -2,25 +2,25 @@
 
 /**
  * @file
- * Contains \Drupal\Component\Render\EscapedMarkupInterface.
+ * Contains \Drupal\Component\Render\EscapableStringInterface.
  */
 
 namespace Drupal\Component\Render;
 
 /**
- * Marks an object's __toString() method as returning escaped markup.
+ * Marks an object's __toString() method as returning an escaped string.
  *
- * This interface should only be used on objects that emit escaped markup from
+ * This interface should only be used on objects that emit escaped strings from
  * their __toString() method. If the output of __toString() contains unescaped
  * markup, it must not be used.
  *
  * @ingroup sanitization
  *
  */
-interface EscapedMarkupInterface extends MarkupInterface, \Countable {
+interface EscapableStringInterface extends MarkupInterface, \Countable {
 
   /**
-   * Returns escaped markup.
+   * Returns an escaped string.
    */
   public function __toString();
 
diff --git a/core/lib/Drupal/Component/Utility/SafeMarkup.php b/core/lib/Drupal/Component/Utility/SafeMarkup.php
index 2a96258..a64ac28 100644
--- a/core/lib/Drupal/Component/Utility/SafeMarkup.php
+++ b/core/lib/Drupal/Component/Utility/SafeMarkup.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Component\Utility;
 
-use Drupal\Component\Render\EscapedMarkup;
+use Drupal\Component\Render\EscapableString;
 use Drupal\Component\Render\FormattableMarkup;
 use Drupal\Component\Render\MarkupInterface;
 
@@ -68,8 +68,8 @@ public static function isSafe($string, $strategy = 'html') {
    * @param string $text
    *   The text to be checked or processed.
    *
-   * @return \Drupal\Component\Render\EscapedMarkupInterface
-   *   An EscapedMarkup object that escapes when rendered to string.
+   * @return \Drupal\Component\Render\EscapableStringInterface
+   *   An EscapableString object that escapes when rendered to string.
    *
    * @ingroup sanitization
    *
@@ -83,7 +83,7 @@ public static function isSafe($string, $strategy = 'html') {
    * @see drupal_validate_utf8()
    */
   public static function checkPlain($text) {
-    return new EscapedMarkup($text);
+    return new EscapableString($text);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Utility/Token.php b/core/lib/Drupal/Core/Utility/Token.php
index 8215837..f6a9aed 100644
--- a/core/lib/Drupal/Core/Utility/Token.php
+++ b/core/lib/Drupal/Core/Utility/Token.php
@@ -7,9 +7,8 @@
 
 namespace Drupal\Core\Utility;
 
-use Drupal\Component\Render\EscapedMarkup;
+use Drupal\Component\Render\EscapableString;
 use Drupal\Component\Render\MarkupInterface;
-use Drupal\Component\Utility\Html;
 use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheableDependencyInterface;
 use Drupal\Core\Cache\CacheBackendInterface;
@@ -208,7 +207,7 @@ public function replace($text, array $data = array(), array $options = array(),
 
     // Escape the tokens, unless they are explicitly markup.
     foreach ($replacements as $token => $value) {
-      $replacements[$token] = $value instanceof MarkupInterface ? $value : new EscapedMarkup($value);
+      $replacements[$token] = $value instanceof MarkupInterface ? $value : new EscapableString($value);
     }
 
     // Optionally alter the list of replacement values.
diff --git a/core/tests/Drupal/Tests/Component/Render/EscapableStringTest.php b/core/tests/Drupal/Tests/Component/Render/EscapableStringTest.php
new file mode 100644
index 0000000..00757d1
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/Render/EscapableStringTest.php
@@ -0,0 +1,69 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Component\Render\EscapableStringTest.
+ */
+
+namespace Drupal\Tests\Component\Render;
+
+use Drupal\Component\Render\EscapableString;
+use Drupal\Component\Render\MarkupInterface;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Tests the EscapableString class.
+ *
+ * @coversDefaultClass \Drupal\Component\Render\EscapableString
+ * @group utility
+ */
+class EscapableStringTest extends UnitTestCase {
+
+  /**
+   * @covers ::__toString
+   * @covers ::jsonSerialize
+   *
+   * @dataProvider providerToString
+   */
+  public function testToString($text, $expected, $message) {
+    $escapeable_string = new EscapableString($text);
+    $this->assertEquals($expected, (string) $escapeable_string, $message);
+    $this->assertEquals($expected, $escapeable_string->jsonSerialize());
+  }
+
+  /**
+   * Data provider for testToString().
+   *
+   * @see testToString()
+   */
+  function providerToString() {
+    // Checks that invalid multi-byte sequences are escaped.
+    $tests[] = array("Foo\xC0barbaz", 'Foo�barbaz', 'Escapes invalid sequence "Foo\xC0barbaz"');
+    $tests[] = array("\xc2\"", '�&quot;', 'Escapes invalid sequence "\xc2\""');
+    $tests[] = array("Fooÿñ", "Fooÿñ", 'Does not escape valid sequence "Fooÿñ"');
+
+    // Checks that special characters are escaped.
+    $script_tag = $this->prophesize(MarkupInterface::class);
+    $script_tag->__toString()->willReturn('<script>');
+    $script_tag = $script_tag->reveal();
+    $tests[] = array($script_tag, '&lt;script&gt;', 'Escapes &lt;script&gt; even inside a SafeString.');
+    $tests[] = array("<script>", '&lt;script&gt;', 'Escapes &lt;script&gt;');
+    $tests[] = array('<>&"\'', '&lt;&gt;&amp;&quot;&#039;', 'Escapes reserved HTML characters.');
+    $specialchars = $this->prophesize(MarkupInterface::class);
+    $specialchars->__toString()->willReturn('<>&"\'');
+    $specialchars = $specialchars->reveal();
+    $tests[] = array($specialchars, '&lt;&gt;&amp;&quot;&#039;', 'Escapes reserved HTML characters even inside a SafeString.');
+
+    return $tests;
+  }
+
+  /**
+   * @covers ::count
+   */
+  public function testCount() {
+    $string = 'Can I please have a <em>kitten</em>';
+    $escapeable_string = new EscapableString($string);
+    $this->assertEquals(strlen($string), $escapeable_string->count());
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php b/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php
index f654fb7..3f0cad6 100644
--- a/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/SafeMarkupTest.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Tests\Component\Utility;
 
-use Drupal\Component\Render\EscapedMarkup;
+use Drupal\Component\Render\EscapableString;
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Component\Render\MarkupInterface;
 use Drupal\Component\Render\MarkupTrait;
@@ -58,27 +58,27 @@ public function testIsSafe() {
    */
   function testCheckPlain($text, $expected, $message) {
     $result = SafeMarkup::checkPlain($text);
-    $this->assertTrue($result instanceof EscapedMarkup);
+    $this->assertTrue($result instanceof EscapableString);
     $this->assertEquals($expected, $result, $message);
   }
 
   /**
-   * Tests Drupal\Component\Render\EscapedMarkup.
+   * Tests Drupal\Component\Render\EscapableString.
    *
    * Verifies that the result of SafeMarkup::checkPlain() is the same as
-   * using EscapedMarkup directly.
+   * using EscapableString directly.
    *
    * @dataProvider providerCheckPlain
    *
    * @param string $text
-   *   The text to provide to the EscapedMarkup constructor.
+   *   The text to provide to the EscapableString constructor.
    * @param string $expected
    *   The expected output from the function.
    * @param string $message
    *   The message to provide as output for the test.
    */
   function testEscapeString($text, $expected, $message) {
-    $result = new EscapedMarkup($text);
+    $result = new EscapableString($text);
     $this->assertEquals($expected, $result, $message);
   }