public function webtreesZipContents(string $zip_file): Collection
    {
        $zip_adapter    = new ZipArchiveAdapter($zip_file, null, 'webtrees');
        $zip_filesystem = new Filesystem(new CachedAdapter($zip_adapter, new Memory()));
        $paths          = new Collection($zip_filesystem->listContents('', true));

        return $paths->filter(static function (array $path): bool {
            return $path['type'] === 'file';
        })
            ->map(static function (array $path): string {
                return $path['path'];
            });
    }