diff --git a/core/lib/Drupal/Core/Extension/ExtensionList.php b/core/lib/Drupal/Core/Extension/ExtensionList.php
index 5d0043e869..747ed16ec3 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionList.php
@@ -9,7 +9,7 @@
 /**
  * Provides available extensions.
  *
- * The extension list is per extension type, like module theme and profile.
+ * The extension list is per extension type, like module, theme and profile.
  */
 abstract class ExtensionList {
 
@@ -207,14 +207,14 @@ protected function getPathnamesCacheId() {
    * Determines if an extension exists in the filesystem.
    *
    * @param string $extension_name
-   *   The extension machine name of the extension.
+   *   The machine name of the extension.
    *
    * @return bool
    *   TRUE if the extension exists (regardless installed or not) and FALSE if
    *   not.
    */
   public function exists($extension_name) {
-    $extensions = $this->list();
+    $extensions = $this->getList();
     return isset($extensions[$extension_name]);
   }
 
@@ -222,13 +222,13 @@ public function exists($extension_name) {
    * Returns the human-readable name of the extension.
    *
    * @param string $extension_name
-   *   The extension machine name.
+   *   The machine name of the extension.
    *
    * @return string
    *   The human-readable name of the extension.
    *
    * @throws \InvalidArgumentException
-   *   If there is no extension with the supplied extension human name.
+   *   If there is no extension with the supplied machine name.
    */
   public function getName($extension_name) {
     return $this->get($extension_name)->info['name'];
@@ -238,7 +238,7 @@ public function getName($extension_name) {
    * Returns a single extension.
    *
    * @param string $extension_name
-   *   The extension machine name.
+   *   The machine name of the extension.
    *
    * @return \Drupal\Core\Extension\Extension
    *   Processed extension object for the given extension machine name.
@@ -247,7 +247,7 @@ public function getName($extension_name) {
    *   If there is no extension with the supplied name.
    */
   public function get($extension_name) {
-    $extensions = $this->list();
+    $extensions = $this->getList();
     if (isset($extensions[$extension_name])) {
       return $extensions[$extension_name];
     }
@@ -259,9 +259,9 @@ public function get($extension_name) {
    * Returns all available extensions.
    *
    * @return \Drupal\Core\Extension\Extension[]
-   *   Processed extension objects, keyed by extension machine name.
+   *   Processed extension objects, keyed by machine name.
    */
-  public function list() {
+  public function getList() {
     if ($this->extensions !== NULL) {
       return $this->extensions;
     }
@@ -282,7 +282,7 @@ public function list() {
    * extensions to this raw listing.
    *
    * @return \Drupal\Core\Extension\Extension[]
-   *   Unprocessed extension objects, keyed by extension machine name.
+   *   Unprocessed extension objects, keyed by machine name.
    */
   protected function doScanExtensions() {
     return $this->getExtensionDiscovery()->scan($this->type);
@@ -292,7 +292,7 @@ protected function doScanExtensions() {
    * Builds the list of extensions.
    *
    * @return \Drupal\Core\Extension\Extension[]
-   *   Processed extension objects, keyed by extension machine name.
+   *   Processed extension objects, keyed by machine name.
    *
    * @throws \Drupal\Core\Extension\InfoParserException
    *   If one of the .info.yml files is incomplete, or causes a parsing error.
@@ -396,16 +396,16 @@ public function getAllInstalledInfo() {
    * Generates the information from .info.yml files for extensions of this type.
    *
    * @return array[]
-   *   An array of arrays of .info.yml entries keyed by the extension machine name.
+   *   An array of arrays of .info.yml entries keyed by the machine name.
    */
   protected function recalculateInfo() {
     return array_map(function (Extension $extension) {
       return $extension->info;
-    }, $this->list());
+    }, $this->getList());
   }
 
   /**
-   * Returns a list of extension file paths keyed by extension machine name.
+   * Returns a list of extension file paths keyed by machine name.
    *
    * @return string[]
    */
@@ -435,7 +435,7 @@ public function getPathnames() {
    *   An array of .info.yml file locations keyed by the extension machine name.
    */
   protected function recalculatePathnames() {
-    $extensions = $this->list();
+    $extensions = $this->getList();
     ksort($extensions);
 
     return array_map(function (Extension $extension) {
@@ -453,7 +453,7 @@ protected function recalculatePathnames() {
    * It is not recommended to call this method except in those rare cases.
    *
    * @param string $extension_name
-   *   The name of the extension for which the filename is requested.
+   *   The machine name of the extension.
    * @param string $pathname
    *   The pathname of the extension which is to be set explicitly rather
    *   than by consulting the dynamic extension listing.
@@ -492,19 +492,20 @@ public function setPathname($extension_name, $pathname) {
    * An installation profile maybe be located in any of the following places:
    *
    * - core/profiles/baz/baz.info.yml
-   * - /profiles/baz/baz.info.yml
+   * - profiles/baz/baz.info.yml
    *
-   * Calling ExtensionList::getFilename('foo') will give you one of the above,
+   * Calling ExtensionList::getPathname('foo') will give you one of the above,
    * depending on where the extension is located and what type it is.
    *
    * @param string $extension_name
-   *   The name of the extension for which the pathname is requested.
+   *   The machine name of the extension for which the pathname is requested.
    *
    * @return string
-   *   The filename of the requested extension's .info.yml file.
+   *   The drupal-root relative filename and path of the requested extension's
+   *   .info.yml file.
    *
    * @throws \InvalidArgumentException
-   *   If there is no extension with the supplied name.
+   *   If there is no extension with the supplied machine name.
    */
   public function getPathname($extension_name) {
     if (isset($this->addedPathNames[$extension_name])) {
@@ -527,7 +528,7 @@ public function getPathname($extension_name) {
    * coming from \SplFileInfo.
    *
    * @param string $extension_name
-   *   The name of the extension for which the path is requested.
+   *   The machine name of the extension for which the path is requested.
    *
    * @return string
    *   The Drupal-root-relative path to the specified extension.
diff --git a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
index cb3a448b00..01fcf59095 100644
--- a/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
+++ b/core/lib/Drupal/Core/Extension/ModuleExtensionList.php
@@ -126,7 +126,7 @@ protected function getProfileDirectories(ExtensionDiscovery $discovery) {
    *   The active profile, if there is one.
    */
   protected function getActiveProfile() {
-    $profiles = $this->profileList->list();
+    $profiles = $this->profileList->getList();
     if ($this->installProfile && isset($profiles[$this->installProfile])) {
       return $profiles[$this->installProfile];
     }
@@ -140,7 +140,7 @@ protected function getActiveProfile() {
   protected function doScanExtensions() {
     $extensions = parent::doScanExtensions();
 
-    $profiles = $this->profileList->list();
+    $profiles = $this->profileList->getList();
     // Modify the active profile object that was previously added to the module
     // list.
     if ($this->installProfile && isset($profiles[$this->installProfile])) {
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index ea7be41c4b..f54f28057c 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -993,7 +993,7 @@ function system_get_info($type, $name = NULL) {
  * @param \Drupal\Core\Extension\Extension[] $modules
  *   The array of all module info.
  *
- * @deprecated in Drupal 8.4.x and will be removed before Drupal 9.0.0. This
+ * @deprecated in Drupal 8.5.0 and will be removed before Drupal 9.0.0. This
  *   function is no longer used in Drupal core.
  *
  * @see https://www.drupal.org/node/2709919
diff --git a/core/tests/Drupal/KernelTests/Core/Extension/ModuleExtensionListTest.php b/core/tests/Drupal/KernelTests/Core/Extension/ModuleExtensionListTest.php
index c40fcee98a..0ab7de5d23 100644
--- a/core/tests/Drupal/KernelTests/Core/Extension/ModuleExtensionListTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Extension/ModuleExtensionListTest.php
@@ -29,7 +29,7 @@ public function testlist() {
 
     /** @var \Drupal\Core\Extension\ModuleExtensionList $module_extension_list */
     $module_extension_list = \Drupal::service('extension.list.module');
-    $extensions = $module_extension_list->list();
+    $extensions = $module_extension_list->getList();
 
     $this->assertArrayHasKey('testing', $extensions);
     $this->assertEquals(1000, $extensions['testing']->weight);
diff --git a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
index 97bf71cdea..8e1588e926 100644
--- a/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
+++ b/core/tests/Drupal/Tests/Core/Extension/ExtensionListTest.php
@@ -76,7 +76,7 @@ public function testGet() {
   public function testList() {
     $test_extension_list = $this->setupTestExtensionList();
 
-    $extensions = $test_extension_list->list();
+    $extensions = $test_extension_list->getList();
     $this->assertCount(1, $extensions);
     $this->assertEquals('test_name', $extensions['test_name']->getName());
   }