You can browse the source code for the development focus branch or get a copy of the branch using the command:
bzr branch lp:ubuntu-gnome-wallpapers

Ubuntu GNOME Wallpapers has 1 active branch owned by 1 team. There were 1 commit by 1 person in the last month.

Bazaar branches

Name Status Last Modified Last Commit
lp:ubuntu-gnome-wallpapers
Series: trunk
bug 1 Development 2019-10-29 10:12:19 UTC 2019-10-29
23. * Switch build to Python3 - The wal...

Author: Tim Lunn
Revision Date: 2019-10-29 10:12:19 UTC

* Switch build to Python3
  - The wallpapers here are getting fairly old, however some users
    of vanilla-gnome-desktop might still use them

11 of 1 result
You can't create new branches for Ubuntu GNOME Wallpapers.