Which of these is NOT a Linux desktop?

Which of these is NOT a Linux desktop?

• Butterfly
• Gnome
• Cinnamon
• XFCE 

EXPLANATION

 Butterfly is a xterm compatible terminal that runs in your browser.

Features

• xterm compatible (support a lot of unused features!)
• Native browser scroll and search
• Theming in css / sass (20 preset themes) endless possibilities!
• HTML in your terminal! cat images and use <table>
• Multiple sessions support (à la screen -x) to simultaneously access a terminal from several places on the planet!
• Secure authentication with X509 certificates!
• 16,777,216 colors support!
• Keyboard text selection!
• Desktop notifications on terminal output!
• Geolocation from browser!
• May work on firefox too!

https://github.com/paradoxxxzero/butterfly