User Agent Switcher
User Agent Switcher add-on; adds a one click user agent switch to the browser. It adds a menu and tool bar button in the browser. Whenever you want to switch the user agent, use the browser button.
User Agent add on helps in spoofing the browser while performing some attacks.
The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser. The extension is available for Firefox and will run on any platform that this browser supports including Windows, macOS and Linux.