Error message
Warning: Undefined array key "version" in Drupal\Core\Asset\CssCollectionOptimizerLazy->generateHash() (line 42 of core/lib/Drupal/Core/Asset/AssetGroupSetHashTrait.php).
Drupal\Core\Asset\CssCollectionOptimizerLazy->generateHash() (Line: 120)
Drupal\Core\Asset\CssCollectionOptimizerLazy->optimize() (Line: 251)
Drupal\Core\Asset\AssetResolver->getCssAssets() (Line: 288)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAssetLibraries() (Line: 132)
Drupal\Core\Render\HtmlResponseAttachmentsProcessor->processAttachments() (Line: 97)
Drupal\big_pipe\Render\BigPipeResponseAttachmentsProcessor->processAttachments() (Line: 45)
Drupal\Core\EventSubscriber\HtmlResponseSubscriber->onRespond() (Line: 246)
Symfony\Component\EventDispatcher\EventDispatcher::Symfony\Component\EventDispatcher\{closure}() (Line: 206)
Symfony\Component\EventDispatcher\EventDispatcher->callListeners() (Line: 56)
Symfony\Component\EventDispatcher\EventDispatcher->dispatch() (Line: 216)
Symfony\Component\HttpKernel\HttpKernel->filterResponse() (Line: 204)
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: 201)
Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 138)
Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 87)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 53)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 715)
Drupal\Core\DrupalKernel->handle() (Line: 19)
