diff --git a/code/Controller/AssetAdmin.php b/code/Controller/AssetAdmin.php
index ddf90ce0f..14d6542ed 100644
--- a/code/Controller/AssetAdmin.php
+++ b/code/Controller/AssetAdmin.php
@@ -295,7 +295,6 @@ public function apiCreateFile(HTTPRequest $request)
         }
 
         // Check parent record
-        /** @var Folder $parentRecord */
         $parentRecord = null;
         if (!empty($data['ParentID']) && is_numeric($data['ParentID'])) {
             $parentRecord = Folder::get()->byID($data['ParentID']);
@@ -377,7 +376,6 @@ public function apiUploadFile(HTTPRequest $request)
         }
 
         // Check parent record
-        /** @var File $file */
         $file = File::get()->byID($data['ID']);
         if (!$file) {
             $this->jsonError(404, _t(__CLASS__.'.FILE_NOT_FOUND', 'File not found'));
@@ -530,7 +528,6 @@ public function apiHistory(HTTPRequest $request)
     public function legacyRedirectForEditView(HTTPRequest $request): HTTPResponse
     {
         $fileID = $request->param('FileID');
-        /** @var File $file */
         $file = File::get()->byID($fileID);
         $link = $this->getFileEditLink($file) ?: $this->Link();
         return $this->redirect($link);
@@ -569,15 +566,13 @@ protected function getNameGenerator($filename)
     }
 
     /**
-     * @param bool $unlinked
-     * @return ArrayList
+     * @return null
      */
     public function breadcrumbs($unlinked = false)
     {
         return null;
     }
 
-
     /**
      * Don't include class namespace in auto-generated CSS class
      */
@@ -738,7 +733,6 @@ public function fileEditorLinkForm($request = null)
      */
     protected function getAbstractFileForm($id, $name, $context = [])
     {
-        /** @var File $file */
         $file = File::get()->byID($id);
 
         if (!$file) {
@@ -849,7 +843,6 @@ public function getFileHistoryForm($context)
             return null;
         }
 
-        /** @var File $file */
         $file = Versioned::get_version(File::class, $id, $versionId);
         if (!$file) {
             $this->jsonError(404);
@@ -866,7 +859,6 @@ public function getFileHistoryForm($context)
         }
 
         $effectiveContext = array_merge($context, ['Record' => $file]);
-        /** @var FormFactory $scaffolder */
         $scaffolder = Injector::inst()->get(FileHistoryFormFactory::class);
         $form = $scaffolder->getForm($this, 'fileHistoryForm', $effectiveContext);
 
@@ -996,7 +988,6 @@ protected function saveOrPublish(array $data, Form $form, bool $doPublish = fals
         }
 
         $id = (int) $data['ID'];
-        /** @var File $record */
         $record = DataObject::get_by_id(File::class, $id);
 
         if (!$record) {
@@ -1050,7 +1041,6 @@ public function unpublish(array $data, Form $form): HTTPResponse
         }
 
         $id = (int) $data['ID'];
-        /** @var File $record */
         $record = DataObject::get_by_id(File::class, $id);
 
         if (!$record) {
@@ -1093,7 +1083,6 @@ public function getObjectFromData(File $file, $thumbnailLinks = true)
         $object['canEdit'] = $file->canEdit();
         $object['canDelete'] = ($file->hasMethod('canArchive')) ? $file->canArchive() : $file->canDelete();
 
-        /** @var Member $owner */
         $owner = $file->Owner();
 
         if ($owner) {
@@ -1134,7 +1123,6 @@ public function getMinimalistObjectFromData(File $file, $thumbnailLinks = true)
             'visibility' => $file->getVisibility()
         );
 
-        /** @var Folder $parent */
         $parent = $file->Parent();
 
         if ($parent) {
@@ -1145,7 +1133,6 @@ public function getMinimalistObjectFromData(File $file, $thumbnailLinks = true)
             );
         }
 
-        /** @var File $file */
         if ($file->getIsImage()) {
             $thumbnails = $this->generateThumbnails($file, $thumbnailLinks);
 
@@ -1328,7 +1315,6 @@ public function folderCreateForm($request = null)
      */
     public function getFolderCreateForm($parentId = 0)
     {
-        /** @var FolderCreateFormFactory $factory */
         $factory = Injector::inst()->get(FolderCreateFormFactory::class);
         $form = $factory->getForm($this, 'folderCreateForm', [ 'ParentID' => $parentId ]);
 
diff --git a/code/Controller/AssetAdminFieldsExtension.php b/code/Controller/AssetAdminFieldsExtension.php
index e1bd8cc76..9b4ebe261 100644
--- a/code/Controller/AssetAdminFieldsExtension.php
+++ b/code/Controller/AssetAdminFieldsExtension.php
@@ -2,9 +2,13 @@
 
 namespace SilverStripe\AssetAdmin\Controller;
 
+use SilverStripe\Admin\LeftAndMain;
 use SilverStripe\Core\Extension;
 use SilverStripe\View\Requirements;
 
+/**
+ * @extends Extension<LeftAndMain>
+ */
 class AssetAdminFieldsExtension extends Extension
 {
     public function init()
diff --git a/code/Controller/AssetAdminFile.php b/code/Controller/AssetAdminFile.php
index e20d176fa..7009e1073 100644
--- a/code/Controller/AssetAdminFile.php
+++ b/code/Controller/AssetAdminFile.php
@@ -15,7 +15,7 @@
 /**
  * Update File dataobjects to be editable in this asset admin
  *
- * @property File $owner
+ * @extends DataExtension<File>
  */
 class AssetAdminFile extends DataExtension
 {
@@ -176,7 +176,7 @@ public function humanizedChanges($from, $to)
     /**
      * Get the list of all nested files in use
      *
-     * @return SS_List
+     * @return SS_List<File>
      */
     public function getFilesInUse()
     {
diff --git a/code/Extensions/CampaignAdminExtension.php b/code/Extensions/CampaignAdminExtension.php
index 798e28c3c..20545d102 100644
--- a/code/Extensions/CampaignAdminExtension.php
+++ b/code/Extensions/CampaignAdminExtension.php
@@ -2,6 +2,7 @@
 
 namespace SilverStripe\AssetAdmin\Extensions;
 
+use SilverStripe\AssetAdmin\Forms\FileFormFactory;
 use SilverStripe\Assets\File;
 use SilverStripe\Core\Extension;
 use SilverStripe\Forms\FormAction;
@@ -10,7 +11,8 @@
 /**
  * Extension that updates the Popover menu of `FileFormFactory`.
  * This extension will only be applied if the `campaign-admin` module is installed.
- * @package SilverStripe\AssetAdmin\Extensions
+ *
+ * @extends Extension<FileFormFactory>
  */
 class CampaignAdminExtension extends Extension
 {
diff --git a/code/Extensions/RemoteFileModalExtension.php b/code/Extensions/RemoteFileModalExtension.php
index d2bd74826..a6d6deced 100644
--- a/code/Extensions/RemoteFileModalExtension.php
+++ b/code/Extensions/RemoteFileModalExtension.php
@@ -20,7 +20,8 @@
 
 /**
  * Decorates ModalController with an insert-oembed modal
- * @see ModalController
+ *
+ * @extends Extension<ModalController>
  */
 class RemoteFileModalExtension extends Extension
 {
@@ -30,16 +31,6 @@ class RemoteFileModalExtension extends Extension
         'remoteEditFormSchema',
     );
 
-    /**
-     * @return ModalController
-     */
-    public function getOwner()
-    {
-        /** @var ModalController $owner */
-        $owner = $this->owner;
-        return $owner;
-    }
-
     /**
      * @return HTTPRequest
      */
diff --git a/code/Extensions/UsedOnTableExtension.php b/code/Extensions/UsedOnTableExtension.php
index 0240254dd..ddbfa309c 100644
--- a/code/Extensions/UsedOnTableExtension.php
+++ b/code/Extensions/UsedOnTableExtension.php
@@ -2,6 +2,7 @@
 
 namespace SilverStripe\AssetAdmin\Extensions;
 
+use SilverStripe\Admin\Forms\UsedOnTable;
 use SilverStripe\Assets\Folder;
 use SilverStripe\Assets\Shortcodes\FileLink;
 use SilverStripe\Core\Extension;
@@ -10,6 +11,8 @@
 
 /**
  * Hides several types of DataObjects on the "Used On" tab when viewing files
+ *
+ * @extends Extension<UsedOnTable>
  */
 class UsedOnTableExtension extends Extension
 {
diff --git a/code/Forms/AssetFormFactory.php b/code/Forms/AssetFormFactory.php
index f88c2b6ff..7b3c68e77 100644
--- a/code/Forms/AssetFormFactory.php
+++ b/code/Forms/AssetFormFactory.php
@@ -153,7 +153,6 @@ protected function getFormFieldTabs($record, $context = [])
     protected function getSaveAction($record)
     {
         if ($record && $record->isInDB() && $record->canEdit()) {
-            /** @var FormAction $action */
             $action = FormAction::create('save', _t(__CLASS__ . '.SAVE', 'Save'))
                 ->setIcon('save')
                 ->setSchemaState([
@@ -227,10 +226,10 @@ protected function getFormActions(RequestHandler $controller = null, $formName,
      */
     protected function getFormFields(RequestHandler $controller = null, $formName, $context = [])
     {
+        /** @var File $record */
         $record = isset($context['Record']) ? $context['Record'] : null;
 
         // Build standard fields for all folders / files
-        /** @var File $record */
         $fields = new FieldList(
             FieldGroup::create(
                 HeaderField::create('TitleHeader', $record ? $record->Title : null, 1)
@@ -302,7 +301,6 @@ protected function getPopoverActions($record)
      */
     protected function getFormFieldDetailsTab($record, $context = [])
     {
-        /** @var Tab $tab */
         $tab = Tab::create(
             'Details',
             TextField::create('Name', _t(__CLASS__ . '.FILENAME', 'Filename')),
@@ -351,7 +349,6 @@ protected function getPath($record, $context = [])
             if ($context['ParentID'] === 0) {
                 return '/';
             }
-            /** @var File $file */
             $file = File::get()->byID($context['ParentID']);
             if ($file) {
                 return $file->getFilename();
diff --git a/code/Forms/FileFormFactory.php b/code/Forms/FileFormFactory.php
index 89975d85c..1eb0e5658 100644
--- a/code/Forms/FileFormFactory.php
+++ b/code/Forms/FileFormFactory.php
@@ -242,7 +242,6 @@ protected function getPublishAction($record)
 
         // Build action
         $publishText = _t('SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.PUBLISH_BUTTON', 'Publish');
-        /** @var FormAction $action */
         $action = FormAction::create('publish', $publishText)
             ->setIcon('rocket')
             ->setSchemaState([
@@ -469,7 +468,6 @@ protected function getInsertAction($record)
     {
         $action = null;
         if ($record && $record->isInDB() && $record->canView()) {
-            /** @var FormAction $action */
             $action = FormAction::create('insert', 'Insert')
                 ->setIcon('plus-circled')
                 ->setSchemaData(['data' => ['buttonStyle' => 'primary']]);
@@ -485,7 +483,6 @@ protected function getInsertLinkAction($record)
     {
         $action = null;
         if ($record && $record->isInDB() && $record->canView()) {
-            /** @var FormAction $action */
             $action = FormAction::create('insert', _t(__CLASS__ . '.INSERT_LINK', 'Link to file'))
                 ->setSchemaData(['data' => ['buttonStyle' => 'primary']]);
         }
diff --git a/code/Forms/ImageFormFactory.php b/code/Forms/ImageFormFactory.php
index e3a060b88..44c4cda7a 100644
--- a/code/Forms/ImageFormFactory.php
+++ b/code/Forms/ImageFormFactory.php
@@ -37,7 +37,6 @@ protected function getSpecsMarkup($record)
 
     protected function getFormFieldAttributesTab($record, $context = [])
     {
-        /** @var Tab $tab */
         $tab = parent::getFormFieldAttributesTab($record, $context);
 
         $alignments = [
@@ -149,7 +148,6 @@ public function getForm(RequestHandler $controller = null, $name = FormFactory::
             if (!$record) {
                 return;
             }
-            /** @var FieldList $fields */
             $fields = $form->Fields();
 
             $dimensions = $fields->fieldByName('Editor.Placement.Dimensions');
diff --git a/code/Forms/PreviewImageField.php b/code/Forms/PreviewImageField.php
index f1cea853b..b771b3057 100644
--- a/code/Forms/PreviewImageField.php
+++ b/code/Forms/PreviewImageField.php
@@ -38,7 +38,6 @@ public function getSchemaStateDefaults()
     {
         $defaults = parent::getSchemaStateDefaults();
 
-        /** @var File $record */
         if ($record = $this->getRecord()) {
             $parent = $record->Parent();
 
@@ -69,7 +68,7 @@ public function performReadonlyTransformation()
     }
 
     /**
-     * @return DataObject
+     * @return File|null
      */
     public function getRecord()
     {
diff --git a/code/Forms/RemoteFileFormFactory.php b/code/Forms/RemoteFileFormFactory.php
index 28f6bee2e..1020149c2 100644
--- a/code/Forms/RemoteFileFormFactory.php
+++ b/code/Forms/RemoteFileFormFactory.php
@@ -235,7 +235,6 @@ protected function getEditFormFields($context)
         // Get embed
         $this->validateUrl($url);
 
-        /** @var Embeddable $embed */
         $embed = Injector::inst()->create(Embeddable::class, $url);
         $this->validateEmbed($embed);
 
diff --git a/code/GraphQL/FileFilter.php b/code/GraphQL/FileFilter.php
index babfd8ffc..60c215e78 100644
--- a/code/GraphQL/FileFilter.php
+++ b/code/GraphQL/FileFilter.php
@@ -97,7 +97,6 @@ public static function filterList(Filterable $list, $filter)
 
         // Filter unknown id by known child if search is not applied
         if (!$search && isset($filter['anyChildId'])) {
-            /** @var File $child */
             $child = File::get()->byID($filter['anyChildId']);
             $id = $child ? ($child->ParentID ?: 0) : 0;
             if ($id) {
diff --git a/code/GraphQL/Resolvers/AssetAdminResolver.php b/code/GraphQL/Resolvers/AssetAdminResolver.php
index 721932442..642552fbb 100644
--- a/code/GraphQL/Resolvers/AssetAdminResolver.php
+++ b/code/GraphQL/Resolvers/AssetAdminResolver.php
@@ -112,7 +112,6 @@ public static function resolveDeleteFiles($object, array $args, $context, Resolv
         }
         $idList = $args['ids'];
 
-        /** @var DataList $file */
         $files = Versioned::get_by_stage(File::class, Versioned::DRAFT)->byIDs($idList);
         if ($files->count() < count($idList ?? [])) {
             // Find out which files count not be found
@@ -142,7 +141,6 @@ public static function resolveMoveFiles($object, array $args, $context)
         $member = UserContextProvider::get($context);
 
         if ($folderId) {
-            /** @var Folder $folder */
             $folder = Versioned::get_by_stage(Folder::class, Versioned::DRAFT)
                 ->byID($folderId);
             if (!$folder) {
@@ -164,7 +162,6 @@ public static function resolveMoveFiles($object, array $args, $context)
         $files = Versioned::get_by_stage(File::class, Versioned::DRAFT)
             ->byIDs($args['fileIds']);
         $errorFiles = [];
-        /** @var File $file */
         foreach ($files as $file) {
             if ($file->canEdit($member)) {
                 $file->ParentID = $folderId;
@@ -225,7 +222,6 @@ public static function resolveReadDescendantFileCounts($object, array $args, $co
         }
         $ids = $args['ids'];
 
-        /** @var DataList|File[] $files */
         $files = Versioned::get_by_stage(File::class, Versioned::DRAFT)->byIDs($ids);
         if ($files->count() < count($ids ?? [])) {
             $class = File::class;
@@ -253,7 +249,6 @@ public static function resolveReadFileUsage($object, array $args, $context, Reso
         }
         $idList = $args['ids'];
 
-        /** @var DataList|File[] $files */
         $files = Versioned::get_by_stage(File::class, Versioned::DRAFT)->byIDs($idList);
         if ($files->count() < count($idList ?? [])) {
             // Find out which files count not be found
@@ -285,7 +280,7 @@ public static function resolveReadFileUsage($object, array $args, $context, Reso
      * @param array $args
      * @param $context
      * @param $info
-     * @return DataList|Filterable
+     * @return DataList<File>
      * @throws HTTPResponse_Exception
      */
     public static function resolveReadFiles($object, array $args = [], $context = [], $info = null)
diff --git a/code/GraphQL/Resolvers/FolderTypeResolver.php b/code/GraphQL/Resolvers/FolderTypeResolver.php
index 5fea9a095..a67183fa4 100644
--- a/code/GraphQL/Resolvers/FolderTypeResolver.php
+++ b/code/GraphQL/Resolvers/FolderTypeResolver.php
@@ -51,7 +51,6 @@ public static function resolveFolderChildren(
             ));
         }
 
-        /** @var DataList $list */
         $list = Versioned::get_by_stage(File::class, 'Stage');
         $filter['parentId'] = $object->ID;
         $list = FileFilter::filterList($list, $filter);
diff --git a/code/Helper/ImageThumbnailHelper.php b/code/Helper/ImageThumbnailHelper.php
index 15c102c99..6ec9f3377 100644
--- a/code/Helper/ImageThumbnailHelper.php
+++ b/code/Helper/ImageThumbnailHelper.php
@@ -77,7 +77,6 @@ public function setMaxImageFileSize($size)
      */
     public function run()
     {
-        /** @var File[]|SS_List $files */
         $files = File::get();
         $totalCount = $files->count();
         if (!$totalCount) {