Comment 1 for bug 1750187

Looking at the releases page http://releases.ubuntu.com/

"The cdimage server also hosts releases of other Ubuntu images not found on this server, such as builds for less popular architectures and other non-standard and ***unsupported images***."

Which means that http://cdimage.ubuntu.com/ubuntu-server/daily/current/ will have unsupported images in contrast to https://cloud-images.ubuntu.com/xenial/current/

Does it mean that unsupported images should not contain snapd?

It's quite easy to confuse new users because to find out the distinction between cdimage and cloud-images support status one has to go to http://releases.ubuntu.com/ and read small text carefully.