Comment 1 for bug 1245690

Workaround:

apt-get install simplestreams
sstream-query --max=1 --pretty --keyring /usr/share/keyrings/ubuntu-cloudimage-keyring.gpg http://cloud-images.ubuntu.com/releases/ datatype=image-downloads arch=amd64 ftype=disk1.img|less

This will show you all released images you can sync, together with each key/value pair that you can match against any place you can include a filter (eg. for "uvt-simplestreams-libvirt sync", or "uvt-kvm create" once you have synced something).