Why did the Ubuntu GNOME logo change in 15.10?

Why did the Ubuntu GNOME logo change in 15.10?

15.04: 15.10:

(Logos extracted from the plymouth-theme-ubuntu-gnome-logo packages of the respective versions.)

Solution 1:

There was some discussion on the Ubuntu GNOME mailing lists about somebody selling Ubuntu GNOME for $30. One of the follow-up emails was from Patrik Bubák, an Ubuntu GNOME dev, who said:

As far as the logo is concerned, borrowing GNOME's was a mistake from day 1. It's highly confusing, and due to its complexity difficult to work with, plus using someone else's logo as our own isn't quite all right, even though certain permissions have been given it will never be clear unless it's completely changed, which it will, soon.

Related:

• Page on Behance.net by Patrik showcasing the new logo
• Announcement of the new artwork on the mailing lists