Download database in gzip
Nope, the UtilitiesController is hard-coded to use .zip:

        $zip = new ZipArchive();

        if ($zip-&gt;open($zipPath, ZipArchive::CREATE) !== true) {
            throw new Exception('Cannot create zip at ' . $zipPath);
        }

        $filename = pathinfo($backupPath, PATHINFO_BASENAME);
        $zip-&gt;addFile($backupPath, $filename);
        $zip-&gt;close();

        return Craft::$app-&gt;getResponse()-&gt;sendFile($zipPath, null, [
            'mimeType' =&gt; 'application/zip',
        ]);