cri-o: Missing libostree-1-1 for Ubuntu Xenial

When trying to install CRI-O from the Ubuntu Atomic PPA, I get the following error:

# apt-get install cri-o
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 cri-o : Depends: libostree-1-1 but it is not installable

I’m on Xenial:

# cat /etc/os-release 
NAME="Ubuntu"
VERSION="16.04.3 LTS (Xenial Xerus)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 16.04.3 LTS"
VERSION_ID="16.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
VERSION_CODENAME=xenial
UBUNTU_CODENAME=xenial

As a matter of fact, there seems to be no libostree-1-1 package for xenial: https://packages.ubuntu.com/search?keywords=libostree-1-1