Pick a browser and operating system combination to get an example User-Agent string for testing.
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36Build a Content-Security-Policy header.
Parse raw HTTP headers, or build a header block.
Build Access-Control-* CORS response headers.
Look up a file's MIME type and Content-Type header.
Build a robots.txt file with allow/disallow rules and sitemap directives.