core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php | 6 +++++-
 core/lib/Drupal/Core/Menu/MenuLinkTree.php                    | 2 +-
 core/modules/system/tests/src/Unit/Menu/MenuLinkTreeTest.php  | 2 +-
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php b/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php
index e3c1643..a26f6b0 100644
--- a/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php
+++ b/core/lib/Drupal/Core/Menu/DefaultMenuLinkTreeManipulators.php
@@ -75,7 +75,11 @@ public function __construct(AccessManagerInterface $access_manager, AccountInter
    *
    * This is compatible with render caching, because of cache context bubbling:
    * conditionally defined cache contexts (i.e. subtrees that are only
-   * accessible to some users) will bubble just
+   * accessible to some users) will bubble just like they do for render arrays.
+   * This is why inaccessible subtrees are deleted, except at the root level: if
+   * we didn't keep those at the root level, we wouldn't be able to know which
+   * cache contexts would cause those subtrees to become accessible again, thus
+   * forcing us to conclude that that subtree is unconditionally inaccessible.
    *
    * @param \Drupal\Core\Menu\MenuLinkTreeElement[] $tree
    *   The menu link tree to manipulate.
diff --git a/core/lib/Drupal/Core/Menu/MenuLinkTree.php b/core/lib/Drupal/Core/Menu/MenuLinkTree.php
index a7d5f7e..4b6502f 100644
--- a/core/lib/Drupal/Core/Menu/MenuLinkTree.php
+++ b/core/lib/Drupal/Core/Menu/MenuLinkTree.php
@@ -171,7 +171,7 @@ public function build(array $tree, $level = 0, CacheableMetadata &$tree_access_c
 
       // Gather the access cacheability of every item in the menu link tree,
       // including inaccessible items. This allows us to render cache the menu
-      // tree, yet still automatically the rendered menu by the same cache
+      // tree, yet still automatically vary the rendered menu by the same cache
       // contexts that the access results vary by.
       // However, if $data->access is not an AccessResultInterface object, this
       // still will render the menu link, because this method does not want to
diff --git a/core/modules/system/tests/src/Unit/Menu/MenuLinkTreeTest.php b/core/modules/system/tests/src/Unit/Menu/MenuLinkTreeTest.php
index 0cd0c1d..d699a8e 100644
--- a/core/modules/system/tests/src/Unit/Menu/MenuLinkTreeTest.php
+++ b/core/modules/system/tests/src/Unit/Menu/MenuLinkTreeTest.php
@@ -71,7 +71,7 @@ protected function setUp() {
    *    itself, because it may be dynamic. For this reason, MenuLinkInterface
    *    extends CacheableDependencyInterface. It allows any menu link plugin to
    *    mark itself as uncacheable (max-age=0) or dynamic (by specifying cache
-   *    tags and/or contexts), to indicate the extent of dynamicness.
+   *    tags and/or contexts), to indicate the extent of dynamism.
    *    This means there are two cases:
    *    a. permanently cacheable, no cache tags, no cache contexts
    *    b. anything else: non-permanently cacheable, and/or cache tags, and/or