User-Agent - a string that is sent along to any website you visit. This is a sort of "fingerprint" your browser leaves behind which contains:
- The name and version of your browser;
- The name of the operating system (Mac, Windows, Linux, etc.) and its version;
- Information about some plugins installed on the browser;
- Other information that identifies and exposes you.
Source code: https://github.com/tarampampam/random-user-agent