diff --git a/Classes/Controller/BackendController.php b/Classes/Controller/BackendController.php
index a70a803b48..964e2e9c47 100644
--- a/Classes/Controller/BackendController.php
+++ b/Classes/Controller/BackendController.php
@@ -172,6 +172,9 @@ public function indexAction(string $node = null)
         $rootNodeAggregate = $contentGraph->findRootNodeAggregateByType(
             NodeTypeNameFactory::forSites()
         );
+        if (!$rootNodeAggregate) {
+            throw new \RuntimeException(sprintf('No sites root node found in content repository "%s", while fetching site node "%s"', $contentRepository->id->value, $siteDetectionResult->siteNodeName->value), 1724849303);
+        }
         $rootNode = $rootNodeAggregate->getNodeByCoveredDimensionSpacePoint($defaultDimensionSpacePoint);
 
         $siteNode = $subgraph->findNodeByPath(
diff --git a/Classes/Controller/BackendServiceController.php b/Classes/Controller/BackendServiceController.php
index 0ae563b848..2ad2734943 100644
--- a/Classes/Controller/BackendServiceController.php
+++ b/Classes/Controller/BackendServiceController.php
@@ -164,7 +164,7 @@ protected function initializeController(ActionRequest $request, ActionResponse $
 
     /**
      * Apply a set of changes to the system
-     * @psalm-param list<array<string,mixed>> $changes
+     * @phpstan-param list<array<string,mixed>> $changes
      */
     public function changeAction(array $changes): void
     {
@@ -521,7 +521,7 @@ public function changeBaseWorkspaceAction(string $targetWorkspaceName, string $d
     /**
      * Persists the clipboard node on copy
      *
-     * @psalm-param list<string> $nodes
+     * @phpstan-param list<string> $nodes
      * @return void
      * @throws \Neos\Flow\Property\Exception
      * @throws \Neos\Flow\Security\Exception
@@ -553,7 +553,7 @@ public function clearClipboardAction()
     /**
      * Persists the clipboard node on cut
      *
-     * @psalm-param list<string> $nodes
+     * @phpstan-param list<string> $nodes
      * @throws \Neos\Flow\Property\Exception
      * @throws \Neos\Flow\Security\Exception
      */
@@ -591,7 +591,7 @@ public function initializeGetAdditionalNodeMetadataAction(): void
 
     /**
      * Fetches all the node information that can be lazy-loaded
-     * @psalm-param list<string> $nodes
+     * @phpstan-param list<string> $nodes
      */
     public function getAdditionalNodeMetadataAction(array $nodes): void
     {
@@ -639,7 +639,7 @@ public function initializeGetPolicyInformationAction(): void
     }
 
     /**
-     * @psalm-param list<NodeAddress> $nodes
+     * @phpstan-param list<NodeAddress> $nodes
      */
     public function getPolicyInformationAction(array $nodes): void
     {
@@ -672,7 +672,7 @@ public function getPolicyInformationAction(array $nodes): void
     /**
      * Build and execute a flow query chain
      *
-     * @psalm-param list<array{type: string, payload: array<string|int, mixed>}> $chain
+     * @phpstan-param non-empty-list<array{type: string, payload: array<string|int, mixed>}> $chain
      */
     public function flowQueryAction(array $chain): string
     {
diff --git a/Classes/Domain/Service/UserLocaleService.php b/Classes/Domain/Service/UserLocaleService.php
index edea62a8aa..2caa5556be 100644
--- a/Classes/Domain/Service/UserLocaleService.php
+++ b/Classes/Domain/Service/UserLocaleService.php
@@ -44,7 +44,7 @@ class UserLocaleService
     /**
      * The current user's locale (cached for performance)
      *
-     * @var Locale
+     * @var Locale|null
      */
     protected $userLocaleRuntimeCache;
 
diff --git a/Classes/FlowQueryOperations/NeosUiDefaultNodesOperation.php b/Classes/FlowQueryOperations/NeosUiDefaultNodesOperation.php
index 40d5b629c5..c941c8bef9 100644
--- a/Classes/FlowQueryOperations/NeosUiDefaultNodesOperation.php
+++ b/Classes/FlowQueryOperations/NeosUiDefaultNodesOperation.php
@@ -67,10 +67,13 @@ public function canEvaluate($context)
      */
     public function evaluate(FlowQuery $flowQuery, array $arguments)
     {
+        /** @var array<int,mixed> $context */
+        $context = $flowQuery->getContext();
+
         /** @var Node $siteNode */
-        $siteNode = $flowQuery->getContext()[0];
+        $siteNode = $context[0];
         /** @var Node $documentNode */
-        $documentNode = $flowQuery->getContext()[1] ?? $siteNode;
+        $documentNode = $context[1] ?? $siteNode;
         /** @var string[] $toggledNodes */
         list($baseNodeType, $loadingDepth, $toggledNodes, $clipboardNodesContextPaths) = $arguments;