Complex sentence: The Linux Mint team addressed the issue in another way by developing the "Mint GNOME Shell Extensions" that ran on top of GNOME 3 and allowed it to be used via the traditional desktop metaphor.
Split into simpler sentences: The Linux Mint team addressed the issue in another way by developing the "Mint GNOME Shell Extensions," extensions that ran on top of GNOME 3. These extensions allowed GNOME 3 to be used via the traditional desktop metaphor.