It is assumed MATE as default desktop

https://git.beta.ucr.ac.cr/cslucr/ubuntu-ucr/blob/ansible/ubuntu-ucr/tasks/main.yml#L33 and subsequent assume MATE as default Desktop.

dpkg-query -l mate-desktop in https://git.beta.ucr.ac.cr/cslucr/ubuntu-ucr/blob/ansible/ubuntu-ucr/tasks/main.yml#L34 fails with exit code 1 and the playbook fails with it.