Asset building breaks the site
This ticket is not about how to solve this problem, which has some known causes and some unknown causes, it was just about logging instead of crashing. Check your civi log (ConfigAndLog) or visit https://civicrm.stackexchange.com/questions/37994/why-cant-the-asset-builder-find for help solving the problem.
Upon upgrade of a Drupal 8 site to CiviCRM 5.30.1 from 5.29.something, the site broke completely with this php error in the drupal watchdog:
Civi\Core\Exception\UnknownAssetException: Unrecognized asset name: crm-menubar.css in Civi\Core\AssetBuilder->render() (line 217 of /var/www/drupal/vendor/civicrm/civicrm-core/Civi/Core/AssetBuilder.php).
Missing assets shouldn't break the site.