public function findBundleClasses(): array
    {
        /** @var string[][] $bundleSets */
        $bundleSets = [];

        $modules = $this->packageRepository->findModules();
        foreach ($modules as $module) {
            $extra = $module->getExtra();
            $this->validateBundlesSectionInExtra($extra);
            if (empty($extra['phplist/core']['bundles'])) {
                continue;
            }

            $bundleSets[$module->getName()] = $extra['phplist/core']['bundles'];
        }

        return $bundleSets;
    }