FressRSS/app/views/importExport/sqlite.phtml

<?php
declare(strict_types=1);
/** @var FreshRSS_View $this */
@ob_end_clean();	// Ensure no buffer
header('Content-Type: application/vnd.sqlite3');
header('Content-Disposition: attachment; filename="' . $this->sqliteName . '"');
header('Cache-Control: private, no-store, max-age=0');
header('Last-Modified: ' . gmdate('D, d M Y H:i:s \\G\\M\\T', @filemtime($this->sqlitePath) ?: 0));
header('Content-Length: ' . (@filesize($this->sqlitePath) ?: 0));
readfile($this->sqlitePath);