diff --git a/core/lib/Drupal/Component/PhpStorage/FileReadOnlyStorage.php b/core/lib/Drupal/Component/PhpStorage/FileReadOnlyStorage.php
index 1fb2f217f4..322c43625c 100644
--- a/core/lib/Drupal/Component/PhpStorage/FileReadOnlyStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/FileReadOnlyStorage.php
@@ -69,6 +69,7 @@ public function getFullPath($name) {
    * {@inheritdoc}
    */
   public function writeable() {
+    @trigger_error('writeable() is deprecated in drupal:9.0.0 and will be removed from drupal:10.0.0. No replacement. See https://www.drupal.org/node/2898947', E_USER_DEPRECATED);
     return FALSE;
   }
 
diff --git a/core/lib/Drupal/Component/PhpStorage/FileStorage.php b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
index 704ae00672..a2303b06c6 100644
--- a/core/lib/Drupal/Component/PhpStorage/FileStorage.php
+++ b/core/lib/Drupal/Component/PhpStorage/FileStorage.php
@@ -148,6 +148,7 @@ public function getFullPath($name) {
    * {@inheritdoc}
    */
   public function writeable() {
+    @trigger_error('writeable() is deprecated in drupal:9.0.0 and will be removed from drupal:10.0.0. No replacement. See https://www.drupal.org/node/2898947', E_USER_DEPRECATED);
     return TRUE;
   }
 
diff --git a/core/lib/Drupal/Component/PhpStorage/PhpStorageInterface.php b/core/lib/Drupal/Component/PhpStorage/PhpStorageInterface.php
index 7a370d252a..330e15a1c5 100644
--- a/core/lib/Drupal/Component/PhpStorage/PhpStorageInterface.php
+++ b/core/lib/Drupal/Component/PhpStorage/PhpStorageInterface.php
@@ -55,6 +55,11 @@ public function save($name, $code);
    * Whether this is a writable storage.
    *
    * @return bool
+   *   TRUE if writable, otherwise FALSE.
+   *
+   * @deprecated in drupal:9.0.0 and is removed from drupal:10.0.0. No replacement.
+   *
+   * @see https://www.drupal.org/node/2898947
    */
   public function writeable();
 
diff --git a/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageReadOnlyTest.php b/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageReadOnlyTest.php
index c5df7508d6..48c4c807ef 100644
--- a/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageReadOnlyTest.php
+++ b/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageReadOnlyTest.php
@@ -79,8 +79,10 @@ public function testReadOnly() {
 
   /**
    * @covers ::writeable
+   * @group legacy
+   * @expectedDeprecation writeable() is deprecated in drupal:9.0.0 and will be removed from drupal:10.0.0. No replacement. See https://www.drupal.org/node/2898947
    */
-  public function testWriteable() {
+  public function testWritable() {
     $php_read = new FileReadOnlyStorage($this->readonlyStorage);
     $this->assertFalse($php_read->writeable());
   }
diff --git a/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageTest.php b/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageTest.php
index 6230bdbd7b..63a85b5c83 100644
--- a/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageTest.php
+++ b/core/tests/Drupal/Tests/Component/PhpStorage/FileStorageTest.php
@@ -48,8 +48,10 @@ public function testCRUD() {
 
   /**
    * @covers ::writeable
+   * @group legacy
+   * @expectedDeprecation writeable() is deprecated in drupal:9.0.0 and will be removed from drupal:10.0.0. No replacement. See https://www.drupal.org/node/2898947
    */
-  public function testWriteable() {
+  public function testWritable() {
     $php = new FileStorage($this->standardSettings);
     $this->assertTrue($php->writeable());
   }