diff --git a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
index b321881..4d50933 100644
--- a/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
@@ -96,9 +96,8 @@ class ExtensionDiscovery {
    *   The extension type to search for. One of 'profile', 'module', 'theme', or
    *   'theme_engine'.
    * @param bool $include_tests
-   *   (optional) Whether to include test extensions. Defaults to FALSE when not
-   *   in a test environment; i.e., all 'tests' directories are excluded in the
-   *   search.
+   *   (optional) Whether to explicitly include or exclude test extensions. By
+   *   default, test extensions are only discovered when in a test environment.
    *
    * @return \Drupal\Core\Extension\Extension[]
    *   An associative array of Extension objects, keyed by extension name.
@@ -199,8 +198,6 @@ public function scan($type, $include_tests = NULL) {
    * Sets installation profile directories based on current site settings.
    *
    * @return $this
-   *
-   * @todo Move installation profiles into Settings (including directory paths).
    */
   public function setProfileDirectoriesFromSettings() {
     $this->profileDirectories = array();
@@ -226,7 +223,8 @@ public function setProfileDirectoriesFromSettings() {
    * Gets the installation profile directories to be scanned.
    *
    * @return array
-   *   A list of installation profile directory paths relative to system root.
+   *   A list of installation profile directory paths relative to the system
+   *   root directory.
    */
   public function getProfileDirectories() {
     return $this->profileDirectories;
@@ -235,8 +233,9 @@ public function getProfileDirectories() {
   /**
    * Sets explicit profile directories to scan.
    *
-   * @param array $profileDirectories
-   *   A list of installation profile directories to search for extensions.
+   * @param array $paths
+   *   A list of installation profile directory paths relative to the system
+   *   root directory (without trailing slash) to search for extensions.
    *
    * @return $this
    */