models/classes/runner/QtiRunnerService.php
private function isThemeSwitcherEnabled()
    {
        /** @var \common_ext_ExtensionsManager $extensionsManager */
        $extensionsManager = $this->getServiceLocator()->get(\common_ext_ExtensionsManager::SERVICE_ID);
        $config = $extensionsManager->getExtensionById("taoTests")->getConfig("test_runner_plugin_registry");

        return array_key_exists(self::TOOL_ITEM_THEME_SWITCHER_KEY, $config)
            && $config[self::TOOL_ITEM_THEME_SWITCHER_KEY]["active"] === true;
    }
private function isThemeSwitcherEnabled()
    {
        /** @var \common_ext_ExtensionsManager $extensionsManager */
        $extensionsManager = $this->getServiceLocator()->get(\common_ext_ExtensionsManager::SERVICE_ID);
        $config = $extensionsManager->getExtensionById("taoTests")->getConfig("test_runner_plugin_registry");

        return array_key_exists(self::TOOL_ITEM_THEME_SWITCHER_KEY, $config)
            && $config[self::TOOL_ITEM_THEME_SWITCHER_KEY]["active"] === true;
    }
Returns that the Theme Switcher Plugin is enabled or not

@return bool
@throws \common_ext_ExtensionException