File system settings page gives "'temporary' is not a supported key"

Same issue on all Drupal 11 projects, while Drupal 10 projects work fine. So I guess it's a Drupal 11 issue?

I've not been able to reproduce this bug on Drupal 11. Are there any modules on the site that could modify the file module's configuration?

@cilefen thanks for your quick reaction. That's really strange.

We use a couple of contrib modules, but none that affects this form.
Debugging this in ValidKeysConstraintValidator shows that the value that's being checked is:

[
  temporary => string (6) "../tmp"
]

This is the related settings.php entry, which looks fine to me:

// Temp directory path:
$settings["file_temp_path"] = "../tmp";

In the settings UI the value looks like this:

Temporary directory
../tmp
A local file system path where temporary files will be stored. This directory should not be accessible over the web. This must be changed in settings.php.

This is the backtrace:

Drupal\Core\TypedData\Validation\RecursiveContextualValidator->validateConstraints() (Line: 154)
Drupal\Core\TypedData\Validation\RecursiveContextualValidator->validateNode() (Line: 164)
Drupal\Core\TypedData\Validation\RecursiveContextualValidator->validateNode() (Line: 106)
Drupal\Core\TypedData\Validation\RecursiveContextualValidator->validate() (Line: 93)
Drupal\Core\TypedData\Validation\RecursiveValidator->validate() (Line: 132)
Drupal\Core\TypedData\TypedData->validate() (Line: 209)
Drupal\Core\Form\ConfigFormBase->validateForm()
call_user_func_array() (Line: 82)
Drupal\Core\Form\FormValidator->executeValidateHandlers() (Line: 274)
Drupal\Core\Form\FormValidator->doValidateForm() (Line: 118)
Drupal\Core\Form\FormValidator->validateForm() (Line: 585)
Drupal\Core\Form\FormBuilder->processForm() (Line: 321)
Drupal\Core\Form\FormBuilder->buildForm() (Line: 73)
Drupal\Core\Controller\FormController->getContentResult()
call_user_func_array() (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 593)
Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 183)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 32)
Drupal\big_pipe\StackMiddleware\ContentLength->handle() (Line: 116)
Drupal\page_cache\StackMiddleware\PageCache->pass() (Line: 90)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 50)
Drupal\ban\BanMiddleware->handle() (Line: 96)
Drupal\crowdsec\Middleware->handle() (Line: 263)
Drupal\shield\ShieldMiddleware->bypass() (Line: 162)
Drupal\shield\ShieldMiddleware->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 49)
Drupal\remove_http_headers\StackMiddleware\RemoveHttpHeadersMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 709)
Drupal\Core\DrupalKernel->handle() (Line: 19)

Honestly, I have no idea so far...