To use it anyway, take an Ubuntu Core 18 image, set it up and ssh in ... then:
snap install mir-kiosk
scp the ubuntu-core-desktop snap to it ....
then:
snap install --dangerous ubuntu-core-desktop_0.1_amd64.snap
snap connect ubuntu-core-desktop:account-control
snap connect ubuntu-core-desktop:hardware-observe
snap connect ubuntu-core-desktop:home
snap connect ubuntu-core-desktop:log-observe
snap connect ubuntu-core-desktop:login-session-control
snap connect ubuntu-core-desktop:login-session-observe
snap connect ubuntu-core-desktop:mount-observe
snap connect ubuntu-core-desktop:network-control
snap connect ubuntu-core-desktop:network-setup-control
snap connect ubuntu-core-desktop:physical-memory-observe
snap connect ubuntu-core-desktop:process-control
snap connect ubuntu-core-desktop:removable-media
snap connect ubuntu-core-desktop:shutdown
snap connect ubuntu-core-desktop:system-observe
snap connect ubuntu-core-desktop:x11-plug ubuntu-core-desktop:x11