Original: Derivatives that are recognized but not supported by Canonical are Xubuntu, a "lightweight" distribution based on the Xfce desktop environment instead of GNOME, designed to run better on low-specification computers.
Simplified: Derivatives that are recognized but not supported by Canonical are: Xubuntu, a "lightweight" distribution based on the Xfce desktop environment instead of GNOME, designed to run better on low-specification computers.