Seen on Flow patches on REL1_45->REL1_43
https://integration.wikimedia.org/ci/job/quibble-composer-mysql-php83/10513/console
21:12:20 Including extensions... InvalidArgumentException from line 827 of /workspace/src/includes/registration/ExtensionProcessor.php: It was attempted to load MetricsPlatform twice, from /workspace/src/extensions/MetricsPlatform/extension.json and /workspace/src/extensions/TestKitchen/extension.json.
21:12:20 #0 /workspace/src/includes/registration/ExtensionProcessor.php(286): MediaWiki\Registration\ExtensionProcessor->extractCredits()
21:12:20 #1 /workspace/src/includes/registration/ExtensionProcessor.php(257): MediaWiki\Registration\ExtensionProcessor->extractInfo()
21:12:20 #2 /workspace/src/includes/installer/Task/ExtensionsProvider.php(157): MediaWiki\Registration\ExtensionProcessor->extractInfoFromFile()
21:12:20 #3 /workspace/src/includes/installer/Task/ExtensionsProvider.php(41): MediaWiki\Installer\Task\ExtensionsProvider->getAutoExtensionData()
21:12:20 #4 /workspace/src/includes/installer/Task/TaskRunner.php(155): MediaWiki\Installer\Task\ExtensionsProvider->execute()
21:12:20 #5 /workspace/src/includes/installer/Task/TaskRunner.php(96): MediaWiki\Installer\Task\TaskRunner->runTask()
21:12:20 #6 /workspace/src/includes/installer/Task/TaskRunner.php(41): MediaWiki\Installer\Task\TaskRunner->loadExtensions()
21:12:20 #7 /workspace/src/includes/installer/Installer.php(1471): MediaWiki\Installer\Task\TaskRunner->execute()
21:12:20 #8 /workspace/src/includes/installer/CliInstaller.php(212): MediaWiki\Installer\Installer->performInstallation()
21:12:20 #9 /workspace/src/maintenance/install.php(207): MediaWiki\Installer\CliInstaller->execute()
21:12:20 #10 /workspace/src/maintenance/includes/MaintenanceRunner.php(696): CommandLineInstaller->execute()
21:12:20 #11 /workspace/src/maintenance/doMaintenance.php(88): MediaWiki\Maintenance\MaintenanceRunner->run()
21:12:20 #12 /workspace/src/maintenance/install.php(278): require_once('...')
21:12:20 #13 {main}