diff --git a/core/modules/media_library/src/Form/AddFormBase.php b/core/modules/media_library/src/Form/AddFormBase.php
index 4c1e14ff90..e27babaa02 100644
--- a/core/modules/media_library/src/Form/AddFormBase.php
+++ b/core/modules/media_library/src/Form/AddFormBase.php
@@ -422,8 +422,11 @@ protected function buildSelectedItemElement(MediaInterface $media, array $form,
           '#title' => $this->t('Select @name', ['@name' => $media->label()]),
           '#title_display' => 'invisible',
           '#return_value' => $media->id(),
-          // Force disable the checkbox. It should only be enabled via
-          // JavaScript.
+          // The checkbox’s value is never processed by this form. It is present
+          // for usability and accessibility reasons, and only used by
+          // JavaScript to track whether or not this media item is selected. The
+          // hidden ‘current_selection’ field is used to store the actual IDs of
+          // selected media items.
           '#value' => FALSE,
         ],
       ],