From two sources: your browser voluntarily discloses a lot of it through standard JavaScript APIs (navigator, screen, Intl, and similar) the moment this page loads, and your own HTTP request headers, sent automatically with every page visit, reveal the rest, such as your IP address, Accept-Language, and User-Agent string. None of it requires special permission - it is exactly what every website you visit already receives from your browser and connection.

Some values yes, some no. Things like your browser language, timezone, screen resolution, or cookie settings can be changed directly in your browser or operating system settings. Values sent by your network connection, like your public IP address or HTTP headers, need a VPN, proxy, or different network to change. A few values, like CPU core count or pixel ratio, reflect your actual hardware and can't be changed without specialized privacy tools.

Yes - most browsers let you override the User-Agent string, either through built-in developer tools (for example Chrome DevTools' network conditions panel) or a browser extension. Some browsers, like Safari and Firefox, also offer a simplified "request desktop site" or similar toggle. Keep in mind this only changes what your browser reports about itself - it doesn't change how the site actually behaves for your real browser engine.

This tool shows you exactly which browser and version you are running so you can compare it yourself, but it does not check for updates. Most modern browsers, such as Chrome, Firefox, Edge, and Safari, update automatically in the background - check for updates manually via the browser's own "About" menu, which also shows if a restart is needed to finish installing one.